US3849602A - Earphone with frequency correction - Google Patents

Earphone with frequency correction Download PDF

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Publication number
US3849602A
US3849602A US00211545A US21154571A US3849602A US 3849602 A US3849602 A US 3849602A US 00211545 A US00211545 A US 00211545A US 21154571 A US21154571 A US 21154571A US 3849602 A US3849602 A US 3849602A
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United States
Prior art keywords
frequency
transducer
earphone
filter
ring
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Expired - Lifetime
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US00211545A
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English (en)
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G Gendin
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Individual
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Individual
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Priority to US00211545A priority Critical patent/US3849602A/en
Priority to GB5985971A priority patent/GB1330968A/en
Priority to FR7201462A priority patent/FR2168143B1/fr
Application granted granted Critical
Publication of US3849602A publication Critical patent/US3849602A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/04—Circuits for transducers, loudspeakers or microphones for correcting frequency response

Definitions

  • Each earphone of a stereo headset comprises an electroacoustic transducer with an audio-frequency signal applied to its input.
  • the electroacoustic transducer is provided with an electric filter connected in series in the current path of the audio-frequency signal and the filter has frequency characteristics which, added to the frequency characteristic of transducer radiation, compensate for frequency attenuation of the high and low end thereof and provide a linear overall radiation characteristic within the assigned frequency band.
  • the object of the present invention is to produce stereo earphones with a high fidelity of sound reproduction, using transducers with a limited reproduced frequency band, thus considerably reducing the earphone production costs.
  • stereo earphones each of which comprises an electroacoustic transducer with an audio-frequency signal applied to its input, wherein the electroacoustic transducer is, according to the invention, provided with an electric filter connected in series with the transmission path of the audio-frequency signal and having frequency characteristics which, added to the frequency characteristic of transducer radiation, compensate for the irregularity of the latter and provide a linear overall radiation characteristic within the assigned frequency band.
  • the present earphones make it possible to obtain high fidelity response while using transducers with a limited reproduced frequency band and thereby to reduce considerably their production costs.
  • FIG. 1 is an axial sectional view a stereo earphone, according to the invention.
  • FIG. 2 is a circuit diagram of the electric filter of each of the stereo earphones.
  • FIG. 3 illustrates the frequency characteristics of the filter arms of each of the stereo earphones and the total filter frequency characteristic.
  • Each of the stereo earphones comprises, according to the invention, a plastic case 1 (FIG. 1) housing a plastic ring 2.
  • the internal diameter of the ring 2 is selected to be equal to the diameter of the radiating part of the cone 4.
  • a latex seal 5 with an opening whose diameter equals the internal diameter of the ring 2 is pasted onto the outside of the ring 2.
  • the opening of said seal 5 and the ring 2 form a sound chamber 6.
  • An electric audio-frequency signal is applied from a source (not shown in the drawing) via a wire 7 to the speaker 3 through an electric filter 8 (FIG. 2).
  • the earphones are also provided with a headband stop adjustment range to enable each user to obtain the most comfortable earphone position.
  • the electric filter 8 (FIG. 2) is an incomplete double T-bridge.
  • the audio-frequency arm of the bridge com prises two series-connected resistors 9 and 10 whose junction point is connected to the zero-potential point via a capacitor 11.
  • the radio-frequency arm of the bridge comprises a capacitor 12 placed between the input and output of the filter 8.
  • the speaker 3 is connected to the output of the filter 8.
  • the electric filter 8 uses a printed-circuit board mounted on a magnetic circuit 13 (FIG. 1) of the speaker 3.
  • the operation of the present stereo earphones is based on the use of electrodynamic speakers from pocket-type transistorized radios, the frequency characteristic of which is corrected by the electric filter and the sound chamber.
  • the operating band of the frequencies, reproduced by a speaker is a frequency band within which the efficiency attenuation at the cut-off frequencies does not exceed an assigned level (usually between 14 and 18 db). This, however, does not mean that beyond this band the speaker does not reproduce sound at all. In fact, at higher or lower frequencies attentuation increases to 30-40 db or more thus bringing the speaker efficiency to the vanishing point so that at very low or very high frequencies the signals become practically inaudible. But even such a low radiation at these frequencies makes it possible to expand several times the actual range of frequencies reproduced by almost any speaker, provided an electric filter is used.
  • the signal is applied to the speaker not directly but through an electric filter which attenuates the midrange of the incoming signal to the level of the frequencies higher and lower than the cut-off frequencies of the speaker being used, the response in the frequency range reproduced by the speaker can be flattened.
  • the input of the filter 8 receives a broadband signal comprising signals below 1,000 Hz and above 10,000 Hz.
  • a reference mid-band frequency e.g. 1,000 Hz
  • the reactance of the capacitor 11 increases as the frequency is decreased and at the threshold low frequencies (20-40 Hz) it practically ceases to affect the shape of the frequency characteristic.
  • the capacitor 12 closes the filter 8 to frequencies higher than 1,000 I-Iz., while its reactance at frequencies below 1,000 Hz is so high that it practically does not effect this section of the frequency characteristic whereas at the threshold high frequencies (18-20 kHz it is practically a short circuit (curve 15, FIG. 3).
  • the use of the above filter 8 provides the necessary correction of the speaker characteristic.
  • the frequency characteristics of the filter 8, added to the frequency characteristic of the speaker 3, compensate for the irregularity of the latter and provide a linear overall radiation characteristic within the assigned frequency band.
  • a stereophonic effect in the present earphones is achieved by applying an audio-frequency signal to each speaker from a separate signal source.
  • the present earphones provide high-fidelity sound reproduction with the use of transducers with a limited reproduced frequency band thereby considerably reducing the production costs.
  • An earphone comprising a case; an electroacoustic transducer adapted to reproduce sound in the audio 1,600 Hz and attenuated output in both high and low frequency ranges, said filter being effective in the midband frequency of the transducer for attenuating said mid-band frequency to compensate for the attenuation of low and high frequencies and provide a substantially linear overall radiation characteristic within the assigned audio-frequency band.
  • An earphone as claimed in claim I wherein said transducer is mounted in said case and has a radiating portion of given diameter, a ring secured in said case and mounting said transducer, said ring having an opening with a diameter equal to the diameter of said radiating portion of the transducer, and a seal on said ring and having an opening with a diameter equal to the opening in said ring, said opening in the ring and seal forming a sound chamber.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Networks Using Active Elements (AREA)
  • Circuit For Audible Band Transducer (AREA)
US00211545A 1971-12-23 1971-12-23 Earphone with frequency correction Expired - Lifetime US3849602A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US00211545A US3849602A (en) 1971-12-23 1971-12-23 Earphone with frequency correction
GB5985971A GB1330968A (en) 1971-12-23 1971-12-23 Earphones
FR7201462A FR2168143B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1971-12-23 1972-01-17

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00211545A US3849602A (en) 1971-12-23 1971-12-23 Earphone with frequency correction

Publications (1)

Publication Number Publication Date
US3849602A true US3849602A (en) 1974-11-19

Family

ID=22787378

Family Applications (1)

Application Number Title Priority Date Filing Date
US00211545A Expired - Lifetime US3849602A (en) 1971-12-23 1971-12-23 Earphone with frequency correction

Country Status (3)

Country Link
US (1) US3849602A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2168143B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1330968A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3988541A (en) * 1975-01-14 1976-10-26 Iowa State University Research Foundation, Inc. Method and apparatus for frequency compensation of electro-mechanical transducer
US4689818A (en) * 1983-04-28 1987-08-25 Siemens Hearing Instruments, Inc. Resonant peak control
US4764957A (en) * 1984-09-07 1988-08-16 Centre National De La Recherche Scientifique-C.N.R.S. Earpiece, telephone handset and headphone intended to correct individual hearing deficiencies
US5123052A (en) * 1990-02-01 1992-06-16 Brisson Bruce A Method and apparatus for reducing the attenuation and phase shift of low frequency components of audio signals
US6771781B2 (en) 2001-05-08 2004-08-03 Daniel A. Chattin Variable damping circuit for a loudspeaker
WO2011069439A1 (zh) * 2009-12-10 2011-06-16 Chen Xiaoli 一种具有无源音效调节功能的耳机
US20140119553A1 (en) * 2007-03-07 2014-05-01 Personics Holdings, Inc. Acoustic dampening compensation system
RU2574821C2 (ru) * 2010-02-02 2016-02-10 Конинклейке Филипс Электроникс Н.В. Контроллер для компоновки головного телефона

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR823417A (fr) * 1936-09-30 1938-01-20 Perfectionnements aux hauts-parleurs
FR1067128A (fr) * 1952-11-26 1954-06-11 Amplificateur pour sourds
US3038964A (en) * 1956-08-06 1962-06-12 Amar G Bose Loudspeaker system

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3988541A (en) * 1975-01-14 1976-10-26 Iowa State University Research Foundation, Inc. Method and apparatus for frequency compensation of electro-mechanical transducer
US4689818A (en) * 1983-04-28 1987-08-25 Siemens Hearing Instruments, Inc. Resonant peak control
US4764957A (en) * 1984-09-07 1988-08-16 Centre National De La Recherche Scientifique-C.N.R.S. Earpiece, telephone handset and headphone intended to correct individual hearing deficiencies
US5123052A (en) * 1990-02-01 1992-06-16 Brisson Bruce A Method and apparatus for reducing the attenuation and phase shift of low frequency components of audio signals
US6771781B2 (en) 2001-05-08 2004-08-03 Daniel A. Chattin Variable damping circuit for a loudspeaker
US20140119553A1 (en) * 2007-03-07 2014-05-01 Personics Holdings, Inc. Acoustic dampening compensation system
US10123110B2 (en) * 2007-03-07 2018-11-06 Staton Techiya, Llc Acoustic dampening compensation system
US10506329B2 (en) 2007-03-07 2019-12-10 Staton Techiya, Llc Acoustic dampening compensation system
US20200077177A1 (en) * 2007-03-07 2020-03-05 Staton Techiya Llc Acoustic dampening compensation system
US11277682B2 (en) * 2007-03-07 2022-03-15 Staton Techiya, Llc Acoustic dampening compensation system
WO2011069439A1 (zh) * 2009-12-10 2011-06-16 Chen Xiaoli 一种具有无源音效调节功能的耳机
RU2574821C2 (ru) * 2010-02-02 2016-02-10 Конинклейке Филипс Электроникс Н.В. Контроллер для компоновки головного телефона

Also Published As

Publication number Publication date
FR2168143B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1976-07-23
GB1330968A (en) 1973-09-19
FR2168143A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-08-31

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