Patents
Sitemap › H04 - Electric communication technique › H04R - Loudspeakers, microphones, gramophone pick-ups or like acoustic electromechanical transducers; Deaf-aid sets; Public address systems › H04R 3 - Circuits for transducers
Patents for H04R 3 - Circuits for transducers (18,190)
06/1981
06/30/1981US4276442 Protective circuit
06/30/1981CA1104220A1 Gain and impedance switching circuit for an amplifier
06/23/1981US4275269 Public address system
06/11/1981WO1981001636A1 Audio signal processing system using a signal level gain control element
05/1981
05/26/1981CA1102000A1 Detection and monitoring device
05/20/1981EP0028613A1 Protection device or circuit for loudspeakers
05/12/1981CA1100881A1 Sound system apparatus and format
05/12/1981CA1100880A1 Language information system
05/05/1981CA1100412A1 Amplifier and sound reproduction system
04/1981
04/14/1981CA1099342A1 Unbalanced dc voltage detecting circuit
04/07/1981US4260954 Amplifier load correction system
04/07/1981CA1099015A1 Malfunction detector for a dictation system
04/02/1981WO1981000947A1 Crossover circuit
03/1981
03/31/1981CA1098450A1 Small dimension low frequency folded exponential horn loudspeaker with unitary sound path and loudspeaker system including same
03/24/1981US4258329 Noise suppression system
03/17/1981US4257067 Sound enhancement system for television receivers
03/17/1981US4256923 Sound reproducing system utilizing motional feedback and integrated magnetic structure
02/1981
02/24/1981CA1096523A1 Circuit arrangement for preventing feedback
02/17/1981CA1095836A1 Device for electronically generating the radiation effects produced by a rotary loudspeaker
02/11/1981EP0023697A1 Circuitry for driving a signalling loudspeaker
02/03/1981US4249225 Magnetic field transducer systems
01/1981
01/28/1981EP0022840A1 Multiple program audio system
01/27/1981CA1094678A1 Loudspeakers
01/13/1981US4245136 Monitor ampliphones
01/06/1981US4243840 Loudspeaker system
01/06/1981US4243839 Transducer with flux sensing coils
12/1980
12/16/1980US4239938 Multiple input signal digital attenuator for combined output
12/16/1980CA1091588A1 Receiving system having a pre-selected directional rejection characteristic
12/02/1980US4237340 Crossover network for optimizing efficiency and improving response of loudspeaker system
12/02/1980US4237339 Audio teleconferencing
11/1980
11/25/1980US4236118 Stabilized remote sensing high fidelity apparatus
11/25/1980US4236088 Noise-free switching circuit for and method of electronically selecting audio input signals in audio systems
11/13/1980WO1980002477A1 Protection device or circuit for loudspeakers
11/11/1980US4233472 Loudspeaker combination, comprising a plurality of dynamic loudspeakers, which are arranged adjacent each other in substantially one continuous plane
10/1980
10/21/1980US4229619 Method and apparatus for driving a multi way speaker system
10/21/1980US4229618 High-fidelity speaker with negative feedback
10/07/1980US4227049 Audio system for isolating sounds from individual components of drum set-up for selectively mixing
09/1980
09/23/1980US4224470 Headset with limiter circuit
09/16/1980US4223242 Method and circuit for driving a piezoelectric transducer
09/16/1980CA1085742A1 Ear pads with earphones
09/16/1980CA1085741A1 Muting circuit for loudspeaker
09/03/1980EP0014868A1 Vibration generator for an ultrasonic liquid atomiser
08/1980
08/26/1980US4219789 Stereo headphone adapter
08/19/1980CA1083971A1 Pivoted loudspeaker enclosure with visual indicator
08/12/1980CA1083490A1 Loudspeaker
07/1980
07/29/1980US4215241 Sound operated control device
07/24/1980WO1980001529A1 Multiple program audio system
07/23/1980EP0013392A1 Dividing network
07/01/1980US4210873 Gain and impedance switching circuit for an amplifier
06/1980
06/24/1980CA1080126A1 Protective circuit for electroacoustic transducer
06/10/1980US4207442 Driver circuit for electrostatic transducers
06/10/1980US4207430 Optical motional feedback
05/1980
05/20/1980US4204092 Audio image recovery system
05/13/1980CA1077632A1 Method and apparatus for operation of carbon microphones at low average current levels
05/06/1980US4201886 Plural concentric moving coil speaker with push-pull voltage follower direct coupling
04/1980
04/15/1980US4198540 Compensated crossover network
04/02/1980EP0009295A1 Infrared light communication equipment
04/01/1980US4196314 Sound distributing system improvements
03/1980
03/25/1980US4195360 Signal processing circuit
03/18/1980CA1074003A1 Acoustic transducer with a dual purpose piezoelectric element
02/1980
02/06/1980EP0007781A1 Method and apparatus for controlling the current supplied to a load
01/1980
01/22/1980US4185276 Sound and light display
01/15/1980US4184187 Unbalanced DC voltage detecting circuit
01/08/1980US4182930 Detection and monitoring device
01/01/1980US4181819 Unitary panel multiple frequency range speaker system
12/1979
12/25/1979US4180706 Loudspeaker motional feedback system
12/18/1979CA1068218A1 Control system for audio amplifying system having multiple microphones
12/18/1979CA1068140A1 Sound generating system for a sound masking package
12/04/1979US4177431 Loudspeaker-cable interface
11/1979
11/27/1979US4176305 Galvano magnetic position control system
11/27/1979US4176251 Modular switching system
11/20/1979US4175242 Circuit arrangement for the automatic frequency control of an ultrasonic transducer
11/06/1979US4173740 Speaker protection circuit
10/1979
10/16/1979CA1064400A1 Headphone apparatus with reverberation circuits
09/1979
09/25/1979CA1063177A1 Supervisory circuit for monitoring speaker coils
08/1979
08/21/1979US4165445 Circuit for preventing acoustic feedback
08/14/1979US4164715 Feedback elimination system employing notch filter
08/07/1979CA1060120A1 Sonic transducer
07/1979
07/31/1979US4163119 Protective circuit for electroacoustic transducer with hall element and voice coil temperature rise time constant circuit
07/24/1979US4162372 Device for electronically generating the radiation effects produced by a rotary loudspeaker
06/1979
06/19/1979US4158787 Electromechanical transducer-coupled mechanical structure with negative capacitance compensation circuit
06/13/1979EP0002413A1 Method and apparatus for recording sound in a room
05/1979
05/29/1979CA1055401A Loudspeaker system with broad image source
05/22/1979CA1055125A1 Pulse width modulated signal amplifier
05/15/1979US4154979 Woofer efficiency
04/1979
04/24/1979US4151379 Electromagnetic speaker with bucking parallel high and low frequency coils drives sounding board and second diaphragm or external apparatus via magnetic coupling and having adjustable air gap and slot pole piece
04/24/1979CA1053156A1 Low range loudspeaker system
04/10/1979US4149032 Priority mixer control
03/1979
03/20/1979US4145571 Loudspeaker enclosure with acoustically coupled loudspeaker damper
03/13/1979CA1050651A1 Apparatus for measuring the velocity of mechanical low frequency vibrations
02/1979
02/20/1979US4140022 Acoustic imaging apparatus
02/20/1979CA1048937A1 Impulse noise reduction system
02/13/1979US4139734 Pivoted loudspeaker enclosure with visual indicator of optimum listening position
02/08/1979WO1979000046A1 A dereverberation system
02/06/1979US4138594 Small dimension low frequency folded exponential horn loudspeaker with unitary sound path and loudspeaker system including same
02/06/1979CA1047942A1 Input adapter for magazine tape recorder/reproducer
01/1979
01/30/1979US4137510 Frequency band dividing filter
12/1978
12/26/1978US4131760 Multiple microphone dereverberation system
12/19/1978US4130727 Loudspeaker equalization
12/19/1978US4130726 Loudspeaker system equalization
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