Patents
Sitemap › H04 - Electric communication technique › H04R - Loudspeakers, microphones, gramophone pick-ups or like acoustic electromechanical transducers; Deaf-aid sets; Public address systems › H04R 27 - Public address systems
Patents for H04R 27 - Public address systems (2,454)
12/1984
12/18/1984US4489442 Sound actuated microphone system
10/1984
10/23/1984US4479265 Laser microphone
10/02/1984US4475232 Fireman's safety apparatus
07/1984
07/03/1984CA1170337A1 System for controlling distinct devices in a theater
03/1984
03/13/1984US4437189 Sound system for a musical instrument
10/1983
10/25/1983US4412105 Laser microphone
08/1983
08/23/1983US4400591 Simulated space helmet
05/1983
05/31/1983US4385814 System for controlling distinct devices in a theater
05/10/1983US4382398 Method and apparatus for eliminating feedback in stage monitors
03/1983
03/29/1983US4378468 Methods and apparatus for alleviating sound-coupled feedback in conference room sound systems
02/1983
02/15/1983US4374435 Passenger entertainment system transducer failure detector
11/1982
11/16/1982US4359602 Multiple input audio program system
10/1982
10/12/1982US4354061 Sensing coil in hearing aid
10/05/1982CA1132913A1 Public address system
12/1981
12/29/1981CA1115438A1 Audio teleconferencing
12/22/1981US4306388 Restaurant entertainment system
10/1981
10/27/1981US4296664 Sound broadcasting apparatus
09/1981
09/08/1981CA1108541A1 Priority mixer control
09/01/1981US4287388 Drive-in theatre sound distribution system
08/1981
08/11/1981US4283600 Recirculationless concert hall simulation and enhancement system
06/1981
06/30/1981US4276572 Automatic message announcement system
06/23/1981US4275269 Public address system
05/1981
05/12/1981CA1100881A1 Sound system apparatus and format
01/1981
01/28/1981EP0022840A1 Multiple program audio system
12/1980
12/02/1980US4237341 Portable self-contained amplifier and loudspeaker apparatus
12/02/1980US4237339 Audio teleconferencing
07/1980
07/24/1980WO1980001529A1 Multiple program audio system
05/1980
05/20/1980CA1078059A1 Public address apparatus
01/1980
01/15/1980US4184050 Drink service system
09/1979
09/25/1979CA1063177A1 Supervisory circuit for monitoring speaker coils
09/04/1979US4166926 Portable lectern and voice amplifier
08/1979
08/21/1979US4165487 Low power system and method for communicating audio information to patrons having portable radio receivers
06/1979
06/13/1979EP0002413A1 Method and apparatus for recording sound in a room
04/1979
04/10/1979US4149032 Priority mixer control
03/1979
03/06/1979CA1050154A1 Telephone conferencing apparatus
12/1978
12/19/1978CA1044762A1 Speaker supervision in a public address system
09/1978
09/19/1978US4114973 Power supply for transportable devices
08/1978
08/22/1978US4109107 Method and apparatus for frequency compensation of electro-acoustical transducer and its environment
08/15/1978US4107464 Alarm communications system
07/1978
07/11/1978US4100380 Supervisory circuit for monitoring speaker coils
06/1978
06/13/1978US4095261 Audio tape recorder, editor and amplifying system
05/1978
05/16/1978US4090033 Miniature portable public address system
02/1978
02/28/1978US4076957 Portable sound device for public address
12/1977
12/06/1977US4061876 Electronic sound enhancing system
10/1977
10/04/1977US4052561 Lectern with detent-hinged shelf for portable sound system
09/1977
09/06/1977US4047109 Drive-in theater audio system
07/1977
07/19/1977US4037222 Supervision of transducers
05/1977
05/24/1977US4025722 Method and apparatus for recording
03/1977
03/01/1977US4010324 Background noisemasking system
12/1976
12/21/1976US3999014 Padded furniture for reverent atmosphere
11/1976
11/16/1976US3992586 Boardroom sound reinforcement system
11/02/1976US3989908 Speaker supervision in a public address system
09/1976
09/14/1976US3980827 Diversity system for noise-masking
04/1976
04/06/1976US3949325 Audio equalizers for large rooms
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