| Patents for H04R 27 - Public address systems (2,454) |
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| 01/15/1992 | EP0465563A1 Speaker power matching method and apparatus |
| 01/02/1992 | EP0463472A1 Electronic muting circuit for electroacoustic systems or public address systems |
| 12/31/1991 | US5077801 Foreground music system using current amplification |
| 10/23/1991 | EP0453293A2 Sound field variable apparatus |
| 10/15/1991 | US5058169 Public address system |
| 09/26/1991 | DE4008808A1 Setting system for spaced loudspeakers - allows individual adjustment of loudspeaker sound levels to obtain required sound centre |
| 09/11/1991 | CN2084697U Computer automatic warning displayer |
| 08/14/1991 | CN2082936U Small size stereo megaphone |
| 08/14/1991 | CN1053875A Portable type audio reproducing and loudening apparatus |
| 08/07/1991 | CN2082499U Controller of automatic switch of audio amplifier |
| 07/31/1991 | EP0439309A2 Apparatus for reproducing and amplifying sound |
| 07/03/1991 | EP0435300A2 Sound equipment system |
| 06/26/1991 | CN2079840U Multifunctional combined electric megaphone capable of receiving, recording, megaphoning and playing |
| 06/09/1991 | WO1991009396A1 Loudspeaker and horn therefor |
| 06/04/1991 | US5020630 Loudspeaker and horn therefor |
| 05/02/1991 | CA2029048A1 Public address system |
| 04/18/1991 | WO1991005445A1 Hand-carried auditory assistance apparatus |
| 04/03/1991 | CN2074521U Automatic time public address set capable of substituting for electric bell |
| 04/02/1991 | US5004067 Cinema sound system for unperforated screens |
| 02/05/1991 | US4991219 Sound simulation chamber |
| 01/17/1991 | DE3922185A1 Loudspeaker group for telephone conferences - has group of vertically spaced loudspeakers, each with cover, penetrating radiation region of superimposed loudspeaker |
| 01/09/1991 | CN2069190U Handcraft shaped radio microphone |
| 12/26/1990 | CN2068301U Portable shouting unit |
| 12/05/1990 | CN2067054U Microphone without squealing and background noise |
| 10/17/1990 | EP0391933A1 Method and device for generating sound in a space for people. |
| 10/04/1990 | WO1990011669A1 Speaker power matching method and apparatus |
| 09/12/1990 | EP0386846A1 Electro-acoustic system |
| 09/04/1990 | US4955059 Transmitting system |
| 08/29/1990 | EP0384637A1 Point of sale audio-visual advertising system |
| 08/28/1990 | US4953218 Foreground music system using current amplification |
| 08/16/1990 | CA2010001A1 Point of sale audio-visual advertising system |
| 07/11/1990 | EP0377144A2 Method and device for correcting a distortion of the loudness perception of a reproduced-sound presentation |
| 07/11/1990 | EP0377142A2 Method and device for correcting a distortion of the loudness perception of a reproduced sound presentation |
| 07/11/1990 | CN2059288U Multi-functional wireless microphone |
| 05/16/1990 | EP0368355A2 Conference box |
| 04/26/1990 | DE3934672A1 Elektroakustisches verfahren zur darbietung von audiosignalen fuer das richtungsorientierte raeumliche hoeren Electro-acoustic method for presenting audio signals for the direction-oriented spatial hear |
| 03/14/1990 | CN2054605U Microphone type audio amplifier with recording and playing function |
| 02/27/1990 | US4905290 Howling protective apparatus |
| 01/31/1990 | CN2052177U Transistor megaphone with great power |
| 01/23/1990 | US4896360 Public address amplifier |
| 12/27/1989 | CN1038387A Multidimensional stereophonic sound reproduction system |
| 12/14/1989 | WO1989012373A1 Multidimensional stereophonic sound reproduction system |
| 11/14/1989 | US4881123 Voice override and amplitude control circuit |
| 09/21/1989 | WO1989008970A1 Induction loop driving amplifiers |
| 07/13/1989 | DE3833200A1 Method and device for calibrating public address systems |
| 06/06/1989 | US4837829 Acoustic sound system for a room |
| 05/17/1989 | CN2037910U Multifunctional microphone |
| 05/16/1989 | US4831656 Conference microphone for use with hearing impaired amplification system |
| 05/05/1989 | WO1989003919A1 A device for a meeting-hall |
| 04/25/1989 | US4823908 Directional loudspeaker system |
| 04/12/1989 | CN2035946U Controller for mixing of eight-channel microphone |
| 04/11/1989 | US4821329 Audio switch device with timed insertion of substitute signal |
| 03/28/1989 | US4815559 Portable loudspeaker apparatus for use in live performances |
| 02/21/1989 | US4805728 For a musical performer |
| 01/11/1989 | CN2030786U Attracted-disk microphone |
| 01/11/1989 | CN2030785U Telephone receive and pick-up device with background voice adjustable arrangement |
| 01/04/1989 | EP0297975A1 Sound pick-up and reproduction device, particularly for audio conferences |
| 12/21/1988 | EP0296092A2 Arrangement for wireless earphones without batteries and electronic circuits, applicable in audio-systems or audio-visual systems of all kinds |
| 11/30/1988 | EP0293205A2 Public address amplifier |
| 10/11/1988 | US4777529 Auditory subliminal programming system |
| 10/06/1988 | EP0170685A4 Control circuit with plural individual selectable controls. |
| 08/31/1988 | EP0279914A2 Receiving device |
| 08/09/1988 | US4763360 Passenger entertainment system having direct coupled seat receivers |
| 06/14/1988 | EP0226613A4 Noise supression system. |
| 05/10/1988 | CA1236559A1 Hearing aid apparatus |
| 04/20/1988 | CN86210343U Pulse width modulation megaphone |
| 04/05/1988 | US4736115 Control circuit with plural individual selectable controls |
| 03/23/1988 | EP0260726A2 Passenger entertainment system having direct coupled seat receivers |
| 02/02/1988 | US4723293 Hearing aid apparatus |
| 02/02/1988 | US4723292 Voice evacuation system |
| 01/21/1988 | DE3723737A1 Reproduction device for stereophonic signals |
| 10/07/1987 | EP0239914A2 An electronic loudspeaker system having a harmonious sound with multiple adjustable sound levels |
| 09/24/1987 | DE3609165A1 Videoconference room furnishing |
| 09/23/1987 | CN86208319U Transformer for hi fi transistor public-address amplifier |
| 07/01/1987 | EP0226613A1 Noise supression system. |
| 06/10/1987 | EP0224754A2 Electroacoustic discussion arrangement |
| 02/19/1987 | DE3529561A1 Arrangement for replaying a selected audio information from an audio information block of an audio medium |
| 01/21/1987 | CN86201730U Electron horn with multistage and harmonic sound |
| 01/15/1987 | WO1987000366A1 Noise supression system |
| 12/16/1986 | US4630305 Automatic gain selector for a noise suppression system |
| 12/16/1986 | US4630304 Automatic background noise estimator for a noise suppression system |
| 12/16/1986 | CA1215326A1 Motion picture theater loudspeaker system |
| 12/09/1986 | US4628529 Noise suppression system |
| 08/20/1986 | EP0191492A2 Computer-controlled electro-acoustic device |
| 08/13/1986 | CN85200511U Language learning machine for deaf-mutes |
| 07/01/1986 | US4598418 For long distance and humane transporting of livestock |
| 06/17/1986 | US4596041 Participant-identification recording and playback system |
| 06/03/1986 | US4593404 Method of improving the acoustics of a hall |
| 05/06/1986 | CA1204062A1 Console priority control |
| 04/29/1986 | US4586195 Microphone range finder |
| 03/13/1986 | WO1986001670A1 Directional speaker system |
| 02/12/1986 | EP0170685A1 Control circuit with plural individual selectable controls |
| 02/04/1986 | US4569076 Motion picture theater loudspeaker system |
| 12/03/1985 | CA1197470A1 Sound actuated microphone system |
| 08/15/1985 | WO1985003582A1 Control circuit with plural individual selectable controls |
| 04/23/1985 | US4513284 Console priority control |
| 01/29/1985 | US4496022 System for interrelating sound transducers or sound sources and their environment |
| 01/23/1985 | EP0131766A1 Hearing aid |
| 01/08/1985 | US4493101 Anti-howl back device |
| 01/01/1985 | US4491699 Communication apparatus for hostile environments |