| Patents for H04R 3 - Circuits for transducers (18,190) |
|---|
| 10/01/1991 | US5054077 Fader device |
| 09/26/1991 | DE4008808A1 Setting system for spaced loudspeakers - allows individual adjustment of loudspeaker sound levels to obtain required sound centre |
| 09/25/1991 | EP0448121A2 Electronic noise attenuation method and apparatus for use in effecting such method |
| 09/24/1991 | US5051964 Virtual microphone apparatus and method |
| 09/24/1991 | US5051799 Digital output transducer |
| 09/19/1991 | DE4008595A1 Microphone for close speech avoiding background noise - has two sound receivers at slight manual spacing in range of their sensitive surfaces |
| 09/17/1991 | US5050214 Remote control circuit |
| 09/03/1991 | US5046106 Varying loudspeaker spatial characteristics in a vehicle |
| 09/03/1991 | US5046103 Noise reducing system for voice microphones |
| 09/03/1991 | US5046101 Audio dosage control system |
| 08/22/1991 | WO1991012699A1 Circuit arrangement for modifying the output signals of a multi-channel electro-acoustic device |
| 08/21/1991 | EP0442388A1 Circuit arrangement for modifying the output signal of a multi-channel acoustical apparatus |
| 08/20/1991 | CA1287887C Speakerphone using digitally compressed audio to detect acoustic feedback |
| 08/13/1991 | US5040156 Acoustic sensor device with noise suppression |
| 08/06/1991 | CA1287373C Infrared stereo speaker system |
| 07/30/1991 | US5036542 Audio surveillance discouragement apparatus and method |
| 07/30/1991 | US5036228 Temperature compensation circuit for negative impedance driving apparatus |
| 07/25/1991 | WO1991011077A1 Sound reproducing device |
| 07/24/1991 | EP0438317A2 Varying loudspeaker spatial characteristics in a vehicle |
| 07/23/1991 | US5034808 Unified automatic video and audio signal control and distribution system |
| 07/19/1991 | CA2033887A1 Varying loudspeaker spatial characteristics in a vehicle |
| 07/17/1991 | CN1053163A Sound imaging system for video game |
| 07/16/1991 | US5033082 Communication system with active noise cancellation |
| 07/11/1991 | WO1991010284A1 Correction circuit and method for a two-way loudspeaker system |
| 07/10/1991 | CN2080735U Adjustable microphone structure and line arrangement thereof |
| 07/09/1991 | US5031221 Dynamic loudspeaker driving apparatus |
| 07/03/1991 | EP0435337A2 Acoustic apparatus |
| 07/03/1991 | EP0435304A2 Acoustic apparatus and driving apparatus constituting the same |
| 07/03/1991 | EP0435300A2 Sound equipment system |
| 07/02/1991 | US5029215 Automatic calibrating apparatus and method for second-order gradient microphone |
| 07/02/1991 | US5027820 Device for the three-dimensional focusing of an ultrasonic beam |
| 07/02/1991 | US5027659 Ultrasonic imaging device in which electroacoustic transducers are disposed on a convex probe |
| 06/25/1991 | US5027393 Voice conference system using echo cancellers |
| 06/18/1991 | US5025472 Reverberation imparting device |
| 06/13/1991 | DE3940859A1 Active loudspeaker cabinet lined with metallic screening material - to which connections are made from mains interference suppression filter and casing of tweeter |
| 06/11/1991 | US5023914 Acoustical frequency response improving with non-minimum phase circuitry |
| 06/11/1991 | US5023913 Apparatus for changing a sound field |
| 06/11/1991 | CA1284771C Device for attenuating noise in electrical apparatus |
| 06/05/1991 | EP0430513A2 Microphone apparatus |
| 05/29/1991 | EP0429264A2 Microphone apparatus |
| 05/28/1991 | US5020109 Apparatus for modulation of the timbre of an electrical amplifier, in particular for guitars |
| 05/28/1991 | CA2030841A1 Feedback system for a sub-woofer loudspeaker |
| 05/21/1991 | US5018206 Network mounting device for coaxial type speaker |
| 05/21/1991 | US5018202 Electronic noise attenuation system |
| 05/16/1991 | WO1991007066A1 Audio surveillance discouragement apparatus and method |
| 05/16/1991 | DE4025973A1 Sound field corrector with sound effect generator(s) - has switches for generator left and right channel changeover |
| 05/15/1991 | EP0348396A4 Radio receiver speech amplifier circuit |
| 05/14/1991 | US5016280 Electronic filters, hearing aids and methods |
| 05/07/1991 | US5014320 Driving apparatus, and control information storage body and protection circuit therefor |
| 05/07/1991 | US5012890 Acoustic apparatus |
| 05/02/1991 | CA2029048A1 Public address system |
| 04/24/1991 | CN2075840U Sound controlled receiver |
| 04/23/1991 | US5009281 Acoustic apparatus |
| 04/23/1991 | US5009280 Acoustic apparatus |
| 04/18/1991 | DE3934215A1 D=A system with pulse width modulator - is actuated by digital system, while modulator signal is amplified |
| 04/18/1991 | DE3933870A1 Controlling microphones supplied with current over cable audio cores - involves adjustment of supply voltage so that magnitude provides control information |
| 04/16/1991 | US5007707 Integrated sound and video screen |
| 04/10/1991 | EP0420948A1 Process and device for tonal processing |
| 04/09/1991 | US5007104 For a radio |
| 04/03/1991 | EP0122290B1 Speaker |
| 04/02/1991 | US5004066 Acoustic apparatus |
| 03/21/1991 | DE3925919A1 Acoustic transducing system with passing loudspeaker - coupled to active speaker in common housing by air movement |
| 03/20/1991 | EP0417388A2 Body vibrator |
| 03/19/1991 | US5001774 Stereo headphone remote control circuit |
| 03/06/1991 | EP0415779A2 Multi-channel audio system |
| 03/06/1991 | EP0415677A2 Hearing aid having compensation for acoustic feedback |
| 03/06/1991 | EP0415237A2 Active noise control apparatus for domestic appliance |
| 03/05/1991 | US4998281 Effect addition apparatus |
| 03/05/1991 | US4997057 Method and apparatus of expanding acoustic reproduction range |
| 03/01/1991 | CA2023838A1 Enhancing bass |
| 02/28/1991 | DE3928239A1 Data transmission system for remote control - has central control point with interface distributing remote control signals to controlled electronic devices |
| 02/27/1991 | EP0414264A2 Virtual microphone apparatus and method |
| 02/21/1991 | DE3940615C1 Double diaphragm moving coil loudspeaker - dynamically dampens resonant frequency by cross-coupling second coils of moving coils in opposite phase |
| 02/19/1991 | US4995113 Device for processing an audio-frequency electrical signal |
| 02/19/1991 | CA1280374C Multi-way loudspeaker system |
| 02/14/1991 | DE3925921A1 Contactless distance measurement of objects or distance changes - measuring changing voltage value and limiting permissible distances to specified region |
| 02/13/1991 | EP0412902A2 Electroacoustic device for hearing needs including noise cancellation |
| 02/13/1991 | EP0412260A2 Audio reproduction apparatus with frequency-selective amplification for driving loudspeakers internal and external to the set |
| 02/11/1991 | CA2022888A1 Electroacoustic device for hearing needs including noise cancellation |
| 02/06/1991 | EP0411801A2 Communication system with active noise cancellation |
| 02/05/1991 | US4991221 Active speaker system and components therefor |
| 02/05/1991 | US4991151 Elastic pulse generator having a desired predetermined wave form |
| 01/30/1991 | EP0410685A2 System for reducing noise level in vehicular cabin |
| 01/29/1991 | US4989187 Acoustic apparatus |
| 01/29/1991 | CA1279726C Method and apparatus for magnetic transducing |
| 01/24/1991 | DE3939398C1 Protective circuit for electroacoustic transducer - has autotransformer with prim. winding connected to reference potential via cold conductor only during transmit mode |
| 01/23/1991 | EP0409429A2 Loudspeaker drive unit |
| 01/22/1991 | US4987601 Acoustic apparatus |
| 01/22/1991 | US4987564 Acoustic apparatus |
| 01/17/1991 | DE4019529A1 Headset outfit microphone mount and 2 earphones - has hoop shaped to fit over helmet with transducers held clear of outermost plane of ear |
| 01/08/1991 | US4984273 Enhancing bass |
| 01/08/1991 | US4984087 Zoom lens |
| 01/03/1991 | DE3917582A1 Driving and regulating loudspeaker - comparing actual and required diaphragm movement to control constant current source |
| 01/02/1991 | EP0405331A2 Acoustic sensing device with noise cancellation |
| 01/02/1991 | CA1278527C Automotive sound system |
| 12/27/1990 | CA1278368C Method and device for improving the sensitivity and the signal-to-noise ratio and piezoelectric transducers comprising a mulitiplicity of parallel mounted sensors |
| 12/26/1990 | CN1048138A Series magnetic circuit and electric circuit system of electroacoustic transducer |
| 12/26/1990 | CN1011024B Muffling feedback circuit of electroacoustic equipment |
| 12/25/1990 | US4980920 Negative impedance driving apparatus having temperature compensation circuit |
| 12/25/1990 | US4980914 Sound field correction system |