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<class-scheme publication-date="2023-02-01" scheme-type="cpc" publication-type="official">
<classification-item breakdown-code="false" not-allocatable="true" level="5" additional-only="false" sort-key="H04R" definition-exists="true" date-revised="2018-08-01" status="published"><classification-symbol>H04R</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS</text></title-part><title-part><text>DEAF-AID SETS</text></title-part><title-part><text>PUBLIC ADDRESS SYSTEMS </text><reference><text>generating mechanical vibrations in general <class-ref scheme="cpc">B06B</class-ref>; transducers for measuring particular variables <class-ref scheme="cpc">G01</class-ref>; transducers in clocks <class-ref scheme="cpc">G04</class-ref>; producing sounds with frequency not determined by supply frequency <class-ref scheme="cpc">G10K</class-ref>; transducers in recording or reproducing heads <class-ref scheme="cpc">G11B</class-ref>; transducers in motors <class-ref scheme="cpc">H02</class-ref></text></reference></title-part></class-title><notes-and-warnings date-revised="2013-01-01"><note type="note"><note-paragraph> This subclass <u>covers</u> : <subnote type="bullet"><note-paragraph> loudspeakers, microphones, <CPC-specific-note>acoustic</CPC-specific-note> transducers <CPC-specific-note>therefor</CPC-specific-note> producing acoustic waves or variations of electric current or voltage, or gramophone pick-ups; </note-paragraph><note-paragraph>arrangements actuated by variations of electric current or voltage for cutting grooves in records;</note-paragraph><note-paragraph> circuits for the above-mentioned <CPC-specific-note>loudspeakers, microphones, acoustic transducers, gramophone pick-ups or</CPC-specific-note> arrangements; </note-paragraph><note-paragraph> monitoring or testing <CPC-specific-note>of the above-mentioned loudspeakers, microphones, acoustic transducers, gramophone pick-ups or arrangements</CPC-specific-note></note-paragraph></subnote></note-paragraph></note><note type="warning"><note-paragraph>In this subclass non-limiting references (in the sense of paragraph 39 of the Guide to the IPC) may still be displayed in the scheme.</note-paragraph></note></notes-and-warnings>
<classification-item breakdown-code="false" not-allocatable="true" level="6" additional-only="false" sort-key="H04R1/00" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/00</classification-symbol>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R1/00" definition-exists="true" ipc-concordant="H04R1/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Details of transducers, </text><CPC-specific-text><text>loudspeakers or microphones</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/005" definition-exists="true" ipc-concordant="H04R1/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/005</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using digitally weighted transducing elements</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/02" definition-exists="true" ipc-concordant="H04R1/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2017-08-01" status="published"><classification-symbol>H04R1/02</classification-symbol><class-title date-revised="2017-08-01"><title-part><text>Casings</text></title-part><title-part><text>Cabinets </text><CPC-specific-text><text>; Supports therefor;</text></CPC-specific-text><text> Mountings therein </text><reference><text><class-ref scheme="cpc">H04R1/28</class-ref> takes precedence </text><CPC-specific-text><text>; attachments for microphones <class-ref scheme="cpc">H04R1/08</class-ref>; mounting of transducers in earpieces <class-ref scheme="cpc">H04R1/1075</class-ref></text></CPC-specific-text></reference></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/021" definition-exists="false" ipc-concordant="H04R1/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/021</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>incorporating only one transducer</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/023" definition-exists="true" ipc-concordant="H04R1/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/023</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Screens for loudspeakers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/025" definition-exists="true" ipc-concordant="H04R1/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/025</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/026" definition-exists="true" ipc-concordant="H04R1/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/026</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Supports for loudspeaker casings</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/028" definition-exists="false" ipc-concordant="H04R1/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/028</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>associated with devices performing functions other than acoustics, e.g. electric candles</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/04" definition-exists="true" ipc-concordant="H04R1/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Structural association of microphone with electric circuitry therefor </text><reference><text>in deaf-aid sets <class-ref scheme="cpc">H04R25/00</class-ref></text></reference></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/06" definition-exists="true" ipc-concordant="H04R1/06" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/06</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Arranging circuit leads</text></title-part><title-part><text>Relieving strain on circuit leads</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/08" definition-exists="true" ipc-concordant="H04R1/08" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2017-08-01" status="published"><classification-symbol>H04R1/08</classification-symbol><class-title date-revised="2017-08-01"><title-part><text>Mouthpieces</text></title-part><title-part><CPC-specific-text><text>Microphones;</text></CPC-specific-text><text> Attachments therefor</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/083" definition-exists="false" ipc-concordant="H04R1/08" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/083</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Special constructions of mouthpieces</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/086" definition-exists="true" ipc-concordant="H04R1/08" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/086</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Protective screens, e.g. all weather or wind screens</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/10" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2017-08-01" status="published"><classification-symbol>H04R1/10</classification-symbol><class-title date-revised="2017-08-01"><title-part><text>Earpieces</text></title-part><title-part><text>Attachments therefor </text><CPC-specific-text><text>; Earphones; Monophonic headphones </text><reference><text><class-ref scheme="cpc">H04R1/28</class-ref> takes precedence; stereophonic headphones <class-ref scheme="cpc">H04R5/033</class-ref></text></reference></CPC-specific-text></title-part></class-title><notes-and-warnings date-revised="2013-01-01"><note type="note"><note-paragraph>This group <u>covers</u> details of headphones, both of monophonic and stereophonic type. </note-paragraph><note-paragraph>When classifying in this group or in its subgroups, aspects relating to stereophonic headphones are to be classified in <class-ref scheme="cpc">H04R5/033</class-ref> as well </note-paragraph></note></notes-and-warnings>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1008" definition-exists="false" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1008</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Earpieces of the supra-aural or circum-aural type</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1016" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1016</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Earpieces of the intra-aural type</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1025" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1025</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Accumulators or arrangements for charging </text><reference><text>secondary cells <u>per se</u> <class-ref scheme="cpc">H01M10/00</class-ref>; charging in general <class-ref scheme="cpc">H02J7/00</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1033" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1033</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Cables or cables storage, e.g. cable reels </text><reference><text>cord reels <u>per se</u> <class-ref scheme="cpc">H02G11/02</class-ref>; arrangements for storing and repeatedly paying-out and re-storing lengths of conductors or cables <class-ref scheme="cpc">B65H75/34</class-ref>; extensible conductors or cables, e.g. self-coiling cords <class-ref scheme="cpc">H01B7/06</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1041" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1041</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Mechanical or electronic switches, or control elements </text><reference><text>switches in general <class-ref scheme="cpc">H01H</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/105" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/105</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Earpiece supports, e.g. ear hooks </text><reference><text>for stereophonic headphones <class-ref scheme="cpc">H04R5/0335</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1058" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1058</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Manufacture or assembly</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/1066" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1066</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Constructional aspects of the interconnection between earpiece and earpiece support </text><reference><text>earpiece support for monophonic headphones <class-ref scheme="cpc">H04R1/105</class-ref>; earpiece support for stereophonic headphones <class-ref scheme="cpc">H04R5/0335</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/1075" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1075</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Mountings of transducers in earphones or headphones</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1083" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/1083</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Reduction of ambient noise </text><reference><text>active noise reduction <u>per se</u> <class-ref scheme="cpc">G10K11/175</class-ref>; protective devices for the ear, e.g. providing acoustic protection <class-ref scheme="cpc">A61F11/06</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/1091" definition-exists="true" ipc-concordant="H04R1/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2016-05-01" status="published"><classification-symbol>H04R1/1091</classification-symbol><class-title date-revised="2016-05-01"><title-part><CPC-specific-text><text>Details not provided for in groups <class-ref scheme="cpc">H04R1/1008</class-ref>&#160;-&#160;<class-ref scheme="cpc">H04R1/1083</class-ref></text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/12" definition-exists="true" ipc-concordant="H04R1/12" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/12</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Sanitary or hygienic devices for mouthpieces or earpieces, e.g. for protecting against infection</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/14" definition-exists="true" ipc-concordant="H04R1/14" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/14</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Throat mountings for microphones</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/16" definition-exists="false" ipc-concordant="H04R1/16" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/16</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Mounting or connecting stylus to transducer with or without damping means</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/18" definition-exists="false" ipc-concordant="H04R1/18" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/18</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Holders for styli</text></title-part><title-part><text>Mounting holders on transducers</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/20" definition-exists="true" ipc-concordant="H04R1/20" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/20</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Arrangements for obtaining desired frequency or directional characteristics </text><reference><text>for stereophonic purpose <class-ref scheme="cpc">H04R5/00</class-ref></text></reference></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/22" definition-exists="true" ipc-concordant="H04R1/22" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/22</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>for obtaining desired frequency characteristic only </text><reference><text>circuit for combining transducers having different responses <class-ref scheme="cpc">H04R3/00</class-ref> </text><CPC-specific-text><text>for hearing aids <class-ref scheme="cpc">H04R25/407</class-ref></text></CPC-specific-text></reference></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/222" definition-exists="false" ipc-concordant="H04R1/22" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/222</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for microphones </text><reference><text><class-ref scheme="cpc">H04R1/24</class-ref>, <class-ref scheme="cpc">H04R1/26</class-ref> take precedence</text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/225" definition-exists="false" ipc-concordant="H04R1/22" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/225</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for telephonic receivers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/227" definition-exists="false" ipc-concordant="H04R1/22" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/227</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using transducers reproducing the same frequency band</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/24" definition-exists="false" ipc-concordant="H04R1/24" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/24</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/245" definition-exists="false" ipc-concordant="H04R1/24" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/245</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>of microphones</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/26" definition-exists="false" ipc-concordant="H04R1/26" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/26</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Spatial arrangements of separate transducers responsive to two or more frequency ranges</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/265" definition-exists="false" ipc-concordant="H04R1/26" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/265</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>of microphones</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/28" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/28</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means </text><CPC-specific-text><reference><text>combinations of transducers with horns, i.e. front-loaded horns <class-ref scheme="cpc">H04R1/30</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/2803" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2803</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/2807" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2807</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Enclosures comprising vibrating or resonating arrangements </text><reference><text>for the reduction of undesired resonances or vibrations <class-ref scheme="cpc">H04R1/2869</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2811" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2811</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2815" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2815</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>of the bass reflex type</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2819" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2819</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2823" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2823</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Vents, i.e. ports, e.g. shape thereof or tuning thereof with damping material </text><reference><text>number or position of ports <class-ref scheme="cpc">H04R1/2815</class-ref>; vents in bandpass type enclosures <class-ref scheme="cpc">H04R1/2846</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="14" additional-only="false" sort-key="H04R1/2826" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2826</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/283" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/283</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using a passive diaphragm</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2834" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2834</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2838" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2838</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>of the bandpass type</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2842" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2842</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2846" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2846</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Vents, i.e. ports, e.g. shape thereof or tuning thereof with damping material </text><reference><text>number or position of ports <class-ref scheme="cpc">H04R1/2838</class-ref>; vents in bass reflex type enclosures <class-ref scheme="cpc">H04R1/2823</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="14" additional-only="false" sort-key="H04R1/2849" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2849</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2853" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2853</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using an acoustic labyrinth or a transmission line</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2857" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2857</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2861" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2861</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using a back-loaded horn</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2865" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2865</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/2869" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2869</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2873" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2873</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2876" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2876</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>by means of damping material, e.g. as cladding </text><reference><text>damping material for tuning desired resonances <class-ref scheme="cpc">H04R1/2807</class-ref>, e.g. in vents <class-ref scheme="cpc">H04R1/2823</class-ref>, <class-ref scheme="cpc">H04R1/2846</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/288" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/288</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2884" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2884</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>by means of the enclosure structure, i.e. strengthening or shape of the enclosure </text><reference><text>by means of Helmholtz resonators <class-ref scheme="cpc">H04R1/2869</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2888" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2888</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/2892" definition-exists="true" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2892</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Mountings or supports for transducers</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="13" additional-only="false" sort-key="H04R1/2896" definition-exists="false" ipc-concordant="H04R1/28" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/2896</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeaker transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/30" definition-exists="true" ipc-concordant="H04R1/30" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/30</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Combinations of transducers with horns, e.g. with mechanical matching means </text><CPC-specific-text><text>, i.e. front-loaded horns</text></CPC-specific-text><reference><text>horns in general <class-ref scheme="cpc">G10K</class-ref>; </text><CPC-specific-text><text>transducer enclosures or mountings using a back-loaded horn <class-ref scheme="cpc">H04R1/2861</class-ref>; application of horns as guiding means to obtain a predetermined directivity characteristic <class-ref scheme="cpc">H04R1/345</class-ref></text></CPC-specific-text></reference></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R1/32" definition-exists="true" ipc-concordant="H04R1/32" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/32</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>for obtaining desired directional characteristic only </text><CPC-specific-text><reference><text>specially adapted for hearing aids <class-ref scheme="cpc">H04R25/40</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/323" definition-exists="false" ipc-concordant="H04R1/32" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/323</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeakers </text><reference><text><class-ref scheme="cpc">H04R1/34</class-ref> and <class-ref scheme="cpc">H04R1/40</class-ref> take precedence</text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/326" definition-exists="false" ipc-concordant="H04R1/32" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/326</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for microphones </text><reference><text><class-ref scheme="cpc">H04R1/34</class-ref> and <class-ref scheme="cpc">H04R1/40</class-ref> take precedence</text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/34" definition-exists="true" ipc-concordant="H04R1/34" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/34</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>by using a single transducer with sound reflecting, diffracting, directing or guiding means </text><CPC-specific-text><reference><text>specially adapted for hearing aids <class-ref scheme="cpc">H04R25/402</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/342" definition-exists="false" ipc-concordant="H04R1/34" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/342</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for microphones</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/345" definition-exists="true" ipc-concordant="H04R1/34" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/345</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeakers</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="12" additional-only="false" sort-key="H04R1/347" definition-exists="true" ipc-concordant="H04R1/34" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/347</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for obtaining a phase-shift between the front and back acoustic wave</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/36" definition-exists="true" ipc-concordant="H04R1/36" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/36</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>by using a single aperture of dimensions not greater than the shortest operating wavelength</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/38" definition-exists="false" ipc-concordant="H04R1/38" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/38</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R1/40" definition-exists="true" ipc-concordant="H04R1/40" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/40</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>by combining a number of identical transducers </text><CPC-specific-text><reference><text>specially adapted for hearing aids <class-ref scheme="cpc">H04R25/405</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/403" definition-exists="true" ipc-concordant="H04R1/40" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/403</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>loud-speakers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R1/406" definition-exists="true" ipc-concordant="H04R1/40" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/406</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>microphones</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/42" definition-exists="false" ipc-concordant="H04R1/42" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/42</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Combinations of transducers with fluid-pressure or other non-electrical amplifying means</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/44" definition-exists="false" ipc-concordant="H04R1/44" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/44</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Special adaptations for subaqueous use, e.g. for hydrophone</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R1/46" definition-exists="true" ipc-concordant="H04R1/46" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R1/46</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Special adaptations for use as contact microphones, e.g. on musical instrument, on stethoscope </text><reference><text>throat mountings <class-ref scheme="cpc">H04R1/14</class-ref></text></reference></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R3/00" definition-exists="true" ipc-concordant="H04R3/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Circuits for transducers </text><CPC-specific-text><text>, loudspeakers or microphones</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R3/002" definition-exists="false" ipc-concordant="H04R3/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/002</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Damping circuit arrangements for transducers, e.g. motional feedback circuits</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R3/005" definition-exists="true" ipc-concordant="H04R3/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/005</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for combining the signals of two or more microphones </text><reference><text>specially adapted for hearing aids <class-ref scheme="cpc">H04R25/407</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R3/007" definition-exists="false" ipc-concordant="H04R3/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/007</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Protection circuits for transducers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R3/02" definition-exists="true" ipc-concordant="H04R3/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>for preventing acoustic reaction </text><CPC-specific-text><text>, i.e. acoustic oscillatory feedback </text><reference><text>specially adapted for hearing aids <class-ref scheme="cpc">H04R25/453</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R3/04" definition-exists="true" ipc-concordant="H04R3/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>for correcting frequency response</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R3/06" definition-exists="false" ipc-concordant="H04R3/06" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/06</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>of electrostatic transducers</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R3/08" definition-exists="false" ipc-concordant="H04R3/08" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/08</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>of electromagnetic transducers</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R3/10" definition-exists="false" ipc-concordant="H04R3/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/10</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>of variable resistance microphones</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R3/12" definition-exists="true" ipc-concordant="H04R3/12" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/12</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>for distributing signals to two or more loudspeakers </text><CPC-specific-text><reference><text>specially adapted for hearing aids <class-ref scheme="cpc">H04R25/407</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R3/14" definition-exists="false" ipc-concordant="H04R3/14" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R3/14</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Cross-over networks</text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R5/00" definition-exists="true" ipc-concordant="H04R5/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R5/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Stereophonic arrangements </text><reference><text>stereophonic pick-ups <class-ref scheme="cpc">H04R9/16</class-ref>, <class-ref scheme="cpc">H04R11/12</class-ref>, <class-ref scheme="cpc">H04R17/08</class-ref>, <class-ref scheme="cpc">H04R19/10</class-ref></text></reference></title-part></class-title><notes-and-warnings date-revised="2013-01-01"><note type="note"><note-paragraph>In this group, the expression &quot;stereophonic arrangements&quot; covers quadraphonic or similar arrangements.</note-paragraph></note></notes-and-warnings>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R5/02" definition-exists="true" ipc-concordant="H04R5/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R5/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Spatial or constructional arrangements of loudspeakers</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R5/023" definition-exists="false" ipc-concordant="H04R5/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R5/023</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>in a chair, pillow</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R5/027" definition-exists="true" ipc-concordant="H04R5/027" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R5/027</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Spatial or constructional arrangements of microphones, e.g. in dummy heads</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R5/033" definition-exists="true" ipc-concordant="H04R5/033" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R5/033</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Headphones for stereophonic communication </text><CPC-specific-text><reference><text>details thereof, e.g. relating to batteries, cables or control elements <class-ref scheme="cpc">H04R1/10</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R5/0335" definition-exists="true" ipc-concordant="H04R5/033" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R5/0335</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Earpiece support, e.g. headbands or neckrests </text><reference><text>for monophonic headphones <class-ref scheme="cpc">H04R1/105</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R5/04" definition-exists="true" ipc-concordant="H04R5/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R5/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Circuit arrangements, </text><CPC-specific-text><text>e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments </text><reference><text>combinations of amplifiers <class-ref scheme="cpc">H03F3/68</class-ref>; stereophonic systems <class-ref scheme="cpc">H04S</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R7/00" definition-exists="true" ipc-concordant="H04R7/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Diaphragms for electromechanical transducers </text><reference><text>in general <class-ref scheme="cpc">F16J3/00</class-ref></text></reference></title-part><title-part><text>Cones </text><reference><text>for musical instruments <class-ref scheme="cpc">G10</class-ref> </text></reference><CPC-specific-text><reference><text>cones, diaphragms or the like, for emitting or receiving sound in general <class-ref scheme="cpc">G10K13/00</class-ref>; Mounting thereof</text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R7/02" definition-exists="true" ipc-concordant="H04R7/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>characterised by the construction</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R7/04" definition-exists="true" ipc-concordant="H04R7/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Plane diaphragms</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R7/045" definition-exists="true" ipc-concordant="H04R7/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/045</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using the distributed mode principle, i.e. whereby the acoustic radiation is emanated from uniformly distributed free bending wave vibration induced in a stiff panel and not from pistonic motion</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R7/06" definition-exists="false" ipc-concordant="H04R7/06" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/06</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>comprising a plurality of sections or layers</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R7/08" definition-exists="false" ipc-concordant="H04R7/08" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/08</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>comprising superposed layers separated by air or other fluid</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R7/10" definition-exists="false" ipc-concordant="H04R7/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/10</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>comprising superposed layers in contact</text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R7/12" definition-exists="false" ipc-concordant="H04R7/12" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/12</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Non-planar diaphragms or cones</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R7/122" definition-exists="false" ipc-concordant="H04R7/12" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/122</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>comprising a plurality of sections or layers</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R7/125" definition-exists="false" ipc-concordant="H04R7/12" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/125</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>comprising a plurality of superposed layers in contact</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R7/127" definition-exists="true" ipc-concordant="H04R7/12" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/127</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>dome-shaped</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R7/14" definition-exists="true" ipc-concordant="H04R7/14" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/14</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>corrugated, pleated or ribbed</text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R7/16" definition-exists="true" ipc-concordant="H04R7/16" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/16</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Mounting or tensioning of diaphragms or cones</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R7/18" definition-exists="true" ipc-concordant="H04R7/18" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/18</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>at the periphery</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R7/20" definition-exists="true" ipc-concordant="H04R7/20" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/20</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Securing diaphragm or cone resiliently to support by flexible material, springs, cords, or strands</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R7/22" definition-exists="true" ipc-concordant="H04R7/22" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/22</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Clamping rim of diaphragm or cone against seating</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R7/24" definition-exists="true" ipc-concordant="H04R7/24" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/24</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Tensioning by means acting directly on free portions of diaphragm or cone</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R7/26" definition-exists="true" ipc-concordant="H04R7/26" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R7/26</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Damping by means acting directly on free portion of diaphragm or cone </text><reference><text>air damping <class-ref scheme="cpc">H04R1/28</class-ref></text></reference></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R9/00" definition-exists="true" ipc-concordant="H04R9/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Transducers of moving-coil, moving-strip, or moving-wire type</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R9/02" definition-exists="true" ipc-concordant="H04R9/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Details</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R9/022" definition-exists="false" ipc-concordant="H04R9/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/022</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Cooling arrangements</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R9/025" definition-exists="true" ipc-concordant="H04R9/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/025</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Magnetic circuit</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R9/027" definition-exists="true" ipc-concordant="H04R9/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/027</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Air gaps using a magnetic fluid</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R9/04" definition-exists="true" ipc-concordant="H04R9/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Construction, mounting, or centering of coil</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R9/041" definition-exists="false" ipc-concordant="H04R9/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/041</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Centering</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="11" additional-only="false" sort-key="H04R9/042" definition-exists="false" ipc-concordant="H04R9/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R9/042</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>by pressurised air</text></CPC-specific-text></title-part></class-title></classification-item>
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<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R11/14" definition-exists="false" ipc-concordant="H04R11/14" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R11/14</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency</text></title-part></class-title></classification-item></classification-item>
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<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R17/02" definition-exists="true" ipc-concordant="H04R17/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R17/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Microphones</text></title-part></class-title>
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<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R17/06" definition-exists="false" ipc-concordant="H04R17/06" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R17/06</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>comprising two or more styli or transducers </text><reference><text><class-ref scheme="cpc">H04R17/08</class-ref> takes precedence</text></reference></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R17/08" definition-exists="false" ipc-concordant="H04R17/08" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R17/08</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R17/10" definition-exists="false" ipc-concordant="H04R17/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R17/10</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R19/00" definition-exists="true" ipc-concordant="H04R19/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Electrostatic transducers</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R19/005" definition-exists="true" ipc-concordant="H04R19/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/005</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using semiconductor materials</text></CPC-specific-text></title-part></class-title></classification-item>
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<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R19/013" definition-exists="false" ipc-concordant="H04R19/01" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/013</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeakers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R19/016" definition-exists="false" ipc-concordant="H04R19/01" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/016</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for microphones</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
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<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R19/04" definition-exists="true" ipc-concordant="H04R19/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Microphones </text><reference><text><class-ref scheme="cpc">H04R19/01</class-ref> takes precedence</text></reference></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R19/06" definition-exists="false" ipc-concordant="H04R19/06" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/06</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Gramophone pick-ups using a stylus</text></title-part><title-part><text>Recorders using a stylus </text><reference><text><class-ref scheme="cpc">H04R19/01</class-ref> takes precedence</text></reference></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R19/08" definition-exists="false" ipc-concordant="H04R19/08" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/08</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>comprising two or more styli or transducers </text><reference><text><class-ref scheme="cpc">H04R19/10</class-ref> takes precedence</text></reference></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R19/10" definition-exists="false" ipc-concordant="H04R19/10" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R19/10</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously</text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R21/00" definition-exists="true" ipc-concordant="H04R21/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Variable-resistance transducers </text><reference><text>gaseous resistance transducers <class-ref scheme="cpc">H04R23/00</class-ref>; magneto-resistive transducers <class-ref scheme="cpc">H04R23/00</class-ref></text></reference></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R21/02" definition-exists="false" ipc-concordant="H04R21/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Microphones</text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R21/021" definition-exists="false" ipc-concordant="H04R21/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/021</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>with granular resistance material</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R21/023" definition-exists="false" ipc-concordant="H04R21/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/023</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>with more than one granular chamber</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R21/025" definition-exists="false" ipc-concordant="H04R21/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/025</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>disposition of the granular chamber in microphones</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R21/026" definition-exists="false" ipc-concordant="H04R21/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/026</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>in which the sound is perpendicular to the current crossing the transducer material</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R21/028" definition-exists="false" ipc-concordant="H04R21/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/028</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>with a fluid as resistance material</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R21/04" definition-exists="false" ipc-concordant="H04R21/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R21/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Gramophone pick-ups using a stylus</text></title-part><title-part><text>Recorders using a stylus</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R23/00" definition-exists="true" ipc-concordant="H04R23/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2016-05-01" status="published"><classification-symbol>H04R23/00</classification-symbol><class-title date-revised="2016-05-01"><title-part><text>Transducers other than those covered by groups <class-ref scheme="cpc">H04R9/00</class-ref>&#160;-&#160;<class-ref scheme="cpc">H04R21/00</class-ref> </text><CPC-specific-text><reference><text>diaphragms for transducers of the distributed-mode type <class-ref scheme="cpc">H04R7/045</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R23/002" definition-exists="false" ipc-concordant="H04R23/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R23/002</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using electrothermic-effect transducer</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R23/004" definition-exists="true" ipc-concordant="H04R23/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R23/004</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using ionised gas</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R23/006" definition-exists="true" ipc-concordant="H04R23/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R23/006</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using solid state devices </text><reference><text>solid state devices <u>per se</u> <class-ref scheme="cpc">H01L</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R23/008" definition-exists="false" ipc-concordant="H04R23/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R23/008</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using optical signals for detecting or generating sound</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R23/02" definition-exists="false" ipc-concordant="H04R23/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R23/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Transducers using more than one principle simultaneously</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R25/00" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/00</classification-symbol><class-title date-revised="2019-05-01"><title-part><text>Deaf-aid sets </text><CPC-specific-text><text>, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception </text><reference><text>electrical stimulation of auditory nerves to promote the auditory function <class-ref scheme="cpc">A61N1/36038</class-ref>; optical stimulation of auditory nerves to promote the auditory function <class-ref scheme="cpc">A61N5/0622</class-ref></text></reference></CPC-specific-text></title-part></class-title><notes-and-warnings date-revised="2013-01-01"><note type="note"><note-paragraph> Classification should be directed to groups <class-ref scheme="cpc">H04R25/02</class-ref>, <class-ref scheme="cpc">H04R25/04</class-ref> or <class-ref scheme="cpc">H04R25/50</class-ref> and its subgroups, if and only if the technical subject in consideration cannot be classified elsewhere under the main group <class-ref scheme="cpc">H04R25/00</class-ref></note-paragraph></note></notes-and-warnings>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/02" definition-exists="false" ipc-concordant="H04R25/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>adapted to be supported entirely by ear</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/04" definition-exists="true" ipc-concordant="H04R25/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>comprising pocket amplifiers</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/30" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/30</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>Monitoring or testing of hearing aids, e.g. functioning, settings, battery power</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/305" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/305</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Self-monitoring or self-testing</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/35" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/35</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using translation techniques</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/353" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/353</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Frequency, e.g. frequency shift or compression</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/356" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/356</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Amplitude, e.g. amplitude shift or compression</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/40" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/40</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Arrangements for obtaining a desired directivity characteristic</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/402" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/402</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using contructional means</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/405" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/405</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>by combining a plurality of transducers</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/407" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/407</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Circuits for combining signals of a plurality of transducers</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/43" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-01-01" status="published"><classification-symbol>H04R25/43</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Electronic input selection or mixing based on input signal analysis, e.g. mixing or selection between microphone and telecoil or between microphones with different directivity characteristics </text><reference><text><class-ref scheme="cpc">H04R25/407</class-ref> takes precedence</text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/45" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/45</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Prevention of acoustic reaction, i.e. acoustic oscillatory feedback</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/453" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/453</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>electronically</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/456" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/456</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>mechanically</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/48" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/48</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>using constructional means for obtaining a desired frequency response </text><reference><text><class-ref scheme="cpc">H04R25/652</class-ref> takes precedence</text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/50" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/50</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Customised settings for obtaining desired overall acoustical characteristics</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/502" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/502</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using analog signal processing</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/505" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/505</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using digital signal processing</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R25/507" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/507</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>implemented by neural network or fuzzy logic</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/55" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/55</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>using an external connection, either wireless or wired</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/552" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/552</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Binaural</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/554" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/554</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>using a wireless connection, e.g. between microphone and amplifier or using Tcoils</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/556" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2022-01-01" status="published"><classification-symbol>H04R25/556</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>External connectors, e.g. plugs or modules </text><reference><text><class-ref scheme="cpc">H04R25/607</class-ref> takes precedence</text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/558" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/558</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>Remote control, e.g. of amplification, frequency</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/60" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2022-01-01" status="published"><classification-symbol>H04R25/60</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>Mounting or interconnection of hearing aid parts, e.g. inside tips, housings or to ossicles </text><reference><text>ear wax retarders, e.g. mounting thereof <class-ref scheme="cpc">H04R25/654</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/602" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/602</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>of batteries</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/603" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2022-01-01" status="published"><classification-symbol>H04R25/603</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>of mechanical or electronic switches or control elements</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/604" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/604</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>of acoustic or vibrational transducers</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R25/606" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/606</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>acting directly on the eardrum, the ossicles or the skull, e.g. mastoid, tooth, maxillary or mandibular bone, or mechanically stimulating the cochlea, e.g. at the oval window</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/607" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2022-01-01" status="published"><classification-symbol>H04R25/607</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>of earhooks</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/609" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2022-01-01" status="published"><classification-symbol>H04R25/609</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>of circuitry </text><reference><text>of electronic switches or control elements <class-ref scheme="cpc">H04R25/603</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/65" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/65</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Housing parts, e.g. shells, tips or moulds, or their manufacture</text></CPC-specific-text></title-part></class-title><notes-and-warnings><note type="note"><note-paragraph>Housing parts for mechanical mounting or interconnection of hearing aid parts covered by <class-ref scheme="cpc">H04R25/60</class-ref> are to be classified in <class-ref scheme="cpc">H04R25/60</class-ref> </note-paragraph></note></notes-and-warnings>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/652" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2022-01-01" status="published"><classification-symbol>H04R25/652</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>Ear tips; Ear moulds </text><reference><text>hybrid ear moulds or post-processing thereof for their customisation <class-ref scheme="cpc">H04R25/659</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R25/654" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/654</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Ear wax retarders</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R25/656" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-01-01" status="published"><classification-symbol>H04R25/656</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Non-customized, universal ear tips, i.e. ear tips which are not specifically adapted to the size or shape of the ear or ear canal</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R25/658" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-01-01" status="published"><classification-symbol>H04R25/658</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Manufacture of housing parts</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R25/659" definition-exists="false" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2022-01-01" status="published"><classification-symbol>H04R25/659</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>Post-processing of hybrid ear moulds for customisation, e.g. in-situ curing</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/70" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R25/70</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Adaptation of deaf aid to hearing loss, e.g. initial electronic fitting</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R25/75" definition-exists="true" ipc-concordant="H04R25/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R25/75</classification-symbol><class-title date-revised="2019-05-01"><title-part><CPC-specific-text><text>Electric tinnitus maskers providing an auditory perception</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R27/00" definition-exists="true" ipc-concordant="H04R27/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R27/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Public address systems </text><reference><text>circuits for preventing acoustic reaction <class-ref scheme="cpc">H04R3/02</class-ref>; circuits for distributing signals to loudspeakers <class-ref scheme="cpc">H04R3/12</class-ref>; </text><CPC-specific-text><text>monitoring or testing arrangements for public address systems <class-ref scheme="cpc">H04R29/007</class-ref></text></CPC-specific-text><text>; amplifiers <class-ref scheme="cpc">H03F</class-ref></text></reference></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R27/02" definition-exists="true" ipc-concordant="H04R27/02" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R27/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Amplifying systems for the deaf</text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R27/04" definition-exists="false" ipc-concordant="H04R27/04" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R27/04</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Electric megaphones</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R29/00" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Monitoring arrangements</text></title-part><title-part><text>Testing arrangements </text><CPC-specific-text><reference><text>for hearing aids <class-ref scheme="cpc">H04R25/30</class-ref>; detection of loudspeaker connection <class-ref scheme="cpc">H04R5/04</class-ref>; sound-field adaptation dependent on speaker detection <class-ref scheme="cpc">H04S7/308</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R29/001" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/001</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for loudspeakers </text><reference><text><class-ref scheme="cpc">H04R29/007</class-ref> takes precedence</text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R29/002" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/002</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Loudspeaker arrays</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R29/003" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/003</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>of the moving-coil type</text></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R29/004" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/004</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for microphones </text><reference><text><class-ref scheme="cpc">H04R29/007</class-ref> takes precedence</text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="9" additional-only="false" sort-key="H04R29/005" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/005</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Microphone arrays</text></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="10" additional-only="false" sort-key="H04R29/006" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/006</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Microphone matching</text></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R29/007" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/007</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for public address systems </text><reference><text>public address systems <u>per se</u> <class-ref scheme="cpc">H04R27/00</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R29/008" definition-exists="true" ipc-concordant="H04R29/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R29/008</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Visual indication of individual signal levels </text><reference><text>visual indication of stereophonic sound image <class-ref scheme="cpc">H04S7/40</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="7" additional-only="false" sort-key="H04R31/00" definition-exists="true" ipc-concordant="H04R31/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R31/00</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor </text><CPC-specific-text><reference><text>manufacture of microstructural arrangements of deformable or non-deformable structures in general <class-ref scheme="cpc">B81C1/00182</class-ref></text></reference></CPC-specific-text></title-part></class-title>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R31/003" definition-exists="true" ipc-concordant="H04R31/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R31/003</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>for diaphragms or their outer suspension</text></CPC-specific-text></title-part></class-title></classification-item>
<classification-item breakdown-code="false" not-allocatable="false" level="8" additional-only="false" sort-key="H04R31/006" definition-exists="true" ipc-concordant="H04R31/00" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R31/006</classification-symbol><class-title date-revised="2013-01-01"><title-part><CPC-specific-text><text>Interconnection of transducer parts </text><reference><text>of diaphragm and outer suspension by moulding <class-ref scheme="cpc">H04R31/003</class-ref></text></reference></CPC-specific-text></title-part></class-title></classification-item></classification-item></classification-item>
<classification-item breakdown-code="true" not-allocatable="true" level="6" additional-only="true" sort-key="H04R201/00" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/00</classification-symbol>
<classification-item breakdown-code="true" not-allocatable="false" level="7" additional-only="true" sort-key="H04R201/00" definition-exists="false" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2019-05-01" status="published"><classification-symbol>H04R2201/00</classification-symbol><class-title date-revised="2019-05-01"><title-part><text>Details of transducers, loudspeakers or microphones covered by <class-ref scheme="cpc">H04R1/00</class-ref> but not provided for in any of its subgroups</text></title-part></class-title>
<classification-item breakdown-code="true" not-allocatable="false" level="8" additional-only="true" sort-key="H04R201/003" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/003</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Mems transducers or their use </text><reference><text>of the electrostatic type <class-ref scheme="cpc">H04R19/005</class-ref></text></reference></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="8" additional-only="true" sort-key="H04R201/02" definition-exists="false" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/02</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Details casings, cabinets or mounting therein for transducers covered by <class-ref scheme="cpc">H04R1/02</class-ref> but not provided for in any of its subgroups</text></title-part></class-title>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/021" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/021</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Transducers or their casings adapted for mounting in or to a wall or ceiling</text></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/023" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/023</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Transducers incorporated in garment, rucksacks or the like</text></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/025" definition-exists="false" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/025</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Transducer mountings or cabinet supports enabling variable orientation of transducer of cabinet</text></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/028" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/028</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Structural combinations of loudspeakers with built-in power amplifiers, e.g. in the same acoustic enclosure </text><reference><text><class-ref scheme="cpc">H04R2499/10</class-ref> takes precedence; Single (sub)woofer with two or more satellite loudspeakers for mid- and high-frequency band reproduction driven via the (sub)woofer <class-ref scheme="cpc">H04R2205/026</class-ref></text></reference></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/029" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/029</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Manufacturing aspects of enclosures transducers</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="8" additional-only="true" sort-key="H04R201/10" definition-exists="false" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/10</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Details of earpieces, attachments therefor, earphones or monophonic headphones covered by <class-ref scheme="cpc">H04R1/10</class-ref> but not provided for in any of its subgroups</text></title-part></class-title>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/103" definition-exists="false" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/103</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Combination of monophonic or stereophonic headphones with audio players, e.g. integrated in the headphone</text></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/105" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/105</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Manufacture of mono- or stereophonic headphone components</text></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/107" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/107</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Monophonic and stereophonic headphones with microphone for two-way hands free communication</text></title-part></class-title></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/109" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/109</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Arrangements to adapt hands free headphones for use on both ears</text></title-part></class-title></classification-item></classification-item>
<classification-item breakdown-code="true" not-allocatable="false" level="8" additional-only="true" sort-key="H04R201/34" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/34</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Directing or guiding sound by means of a phase plug</text></title-part></class-title></classification-item>
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<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R201/401" definition-exists="false" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2201/401</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>2D or 3D arrays of transducers</text></title-part></class-title></classification-item>
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<classification-item breakdown-code="true" not-allocatable="false" level="8" additional-only="true" sort-key="H04R499/10" definition-exists="false" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2499/10</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>General applications</text></title-part></class-title>
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<classification-item breakdown-code="true" not-allocatable="false" level="9" additional-only="true" sort-key="H04R499/13" definition-exists="true" ipc-concordant="CPCONLY" c-set-base-allowed="false" c-set-subsequent-allowed="true" date-revised="2013-01-01" status="published"><classification-symbol>H04R2499/13</classification-symbol><class-title date-revised="2013-01-01"><title-part><text>Acoustic transducers and sound field adaptation in vehicles</text></title-part></class-title></classification-item>
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