Abstract: The disclosed stereo sound pillow has a resilient interior fiberous composite and an essentially nonextendable exterior case completely enclosing the interior composite. Sound speakers having sound outlets from both front and rear sides thereof, and lead wires connected to each speaker, are fixed to a flexible mounting strip: and the mounting strip and speakers are surrounded by the interior composite to hold the sound speakers suspended within the interior composite, spaced apart lengthwise and from the side and end edges thereof, and the lead wires exit from the exterior case adjacent one end edge.

Abstract: Apparatus for providing cross coupling of information on two channels in a two channel transducer. The apparatus preferably comprises a first housing having a first transducer adapted to convert an electrical signal on a first of the channels to sound, a second housing having a second transducer adapted to convert an electrical signal on a second of the channels to sound, the first transducer comprising a first voice coil and the first housing having a further first voice coil, the second transducer comprising a second voice coil and said second housing further having a further second voice coil, the first voice coil being electrically coupled to the further second voice coil and the second voice coil being electrically coupled to the further first voice coil.

Abstract: In the process of forming the effect sound for reproducing a sound field, a down-sampling part for reducing the sampling frequency of the digital signal is disposed before the step of the digital operation which becomes the central part of the forming process, by which a large amount of operation processing is carried out at a low sampling rate. With respect to the direct sound, processing such as gain adjustment is carried out without decreasing the sampling frequency. This results in a sound field control system which permits one to realize a higher quality and natural sound field control effect without significantly increasing the amount of hardware needed.

Abstract: Electro-acoustic system for improving the acoustic of a predetermined room, said system comprising a microphone array having a plurality of microphones and a loudspeaker array having a plurality of loudspeakers, as well as a signal processing unit, interposed between said arrays, said signal processing unit having means for generating reflections, whereby at least one of the microphones is directed in such a manner that it receives at least reflected sound from a sound source in the predetermined room and/or that at least one of the loudspeakers is directed at a reflecting surface in the predetermined room.

Abstract: A sound field correcting device provides for a natural acoustic localization of the outputs of right and left channels of an acoustic sound source. At least one of right and left channel audio signals is delayed to create a phase difference between the right and left channel audio signals, and to thus dislocate a sound in such a way that a listener not positioned equidistant between right and left channel sound sources may perceive the two channels equally.

Abstract: For improved sound reinforcement, especially of the human voice, in situations where clarity and full audience coverage are important, an integrated structure supports a microphone and a speaker unit in an anti-feedback spatial relationship. The single speaker unit, mounted in an elevated position facing the audience, acts as a well-localized "point source", the microphone being located nearby in a working location to the rear of speaker. Despite this proximity, acoustic feedback and resultant "howl" tendencies are suppressed by providing both the microphone and the speaker unit with hypercardioid directivity and locating them in an offset back-to-back relationship such that alignment of their "null" regions combines their attenuation, minimizing feedback. In one embodiment, a lectern table supports the microphone in a working position and mounts an offset vertical pole carrying the speaker unit. The system amplifier may be housed within the lectern table.

Abstract: An audio processing module (20) capable of virtually infinite segmentation of the audio frequency spectrum. The module (20) comprises a first submodule (22), a second submodule (24) and a subwoofer module (28). The first and second submodules (22, 24) are substantially identical, each containing a high pass signal path (112), a high pass band signal path (114) and a low pass band channel (116). A mixed input/output port (29) provides a means for serial chaining of multiple modules.

Abstract: An electroacoustic system for acoustic enhancement of a room that includes a sound source location. The electroacoustic system includes a microphone spaced from the sound source location, an array of loudspeakers arranged in at least four interleaved banks, each bank including at least one loudspeaker, and signal processing electronics connected between the microphone and the speaker banks that includes an input channel, circuitry connecting the microphone to the input channel, a plurality of output channels corresponding in number to the number of speaker banks, circuitry connecting each output channel to a corresponding speaker bank, and at least four statistically independent time-variant reverberation units responsive to input signals from the microphone for producing output signals on the output channels for driving the several banks of speakers.

Abstract: A fetal speaker system and support belt of the present invention includes a belt like housing, a pair of low volume speakers mounted spaced apart, and a casing with a resilient padding material therein. The belt fastens around the abdomen and adjusts accordingly to the growing belly. A radio or other audio transmitting device is maintained in position by a sturdy sleeve on the side of the belt. The electrical conductor connecting the plug to the speakers is mounted within the casing such that the wires do not interfere with the belt wearer. The belt offers sturdy yet stain resistant material for the exterior and a comfortable soft cloth on the interior side to be worn on bare skin if desired. The material is available in a wide variety of fashionable colors and can be designed according to the individual's specifications.

Abstract: A dipole speaker for use with a multichannel sound reproduction system for producing an acoustical ambience signal. The dipole speaker comprises a transducer which is connected to the sound reproduction system so that it receives a difference signal from between the channels thereof. The transducer may be a unitary loudspeaker or a pair of identical, outward-facing loudspeakers. In response to a difference signal, the transducer generates first and second sound pressure lobes which extend in opposite directions from the dipole speaker, and which are 180 degrees out of phase so that they cancel one another out to produce a null zone which extends in a plane about the speaker. The dipole speaker is used in conjunction with conventional direct-path speakers which are connected to the sound reproduction system.

Abstract: An automatic sound volume controller for use with audio equipment mounted on a vehicle adapted that the level of an input audio signal and that of the noises coming inside the cabin in running state are detected, and the difference therebetween is obtained. By use of different gain levels reflecting the level difference, a direct sound signal and an effect sound signal are individually amplified for synthesis. This makes it possible to prevent the added effect sounds from being masked by the running noises because the level of the effect sound signal varies with the noises. As a result, the reproduced sounds supplemented by the effect sounds can be heard clearly while the vehicle is running. With the vehicle in stationary state, the effect sounds are kept from getting excessive, protecting the vehicle passengers from the unpleasant sensation conventionally associated with the apparatus of this kind.

Abstract: There is provided a FMX ID signal detection apparatus for discriminating between a FM broadcasting by means of a FM signal including a sum and difference signals M and S obtained from stereophonically related audio frequency source signals by matrix processing and a FMX broadcasting by means of a FMX composite signal including a compressed difference signal SD obtained by compresssing the dynamic range of the signal S, a FMX identification signal and the signals M and S.

Abstract: A silencer for deadening noise produced with drive of a motor-compressor disposed in a machine compartment of a refrigerator includes a data storage for previously storing sound wave data for every starting condition of the compressor, the sound wave data corresponding to sound waves produced by the compressor during a starting period thereof, the sound wave data being sound wave signals suitable for reducing sound from the compressor by the effect of sound wave interference, a control for determining the starting condition at the starting of the compressor, the control further reading out, from the data storage, the sound wave data corresponding to the determined starting condition, during the starting of the compressor, and a sound producer driven in response to the sound wave data read out from the data storage in the form of an electrical signal, thereby producing sound waves, the sound producer being disposed so that sound is directed to the interior of the machine compartment.

Abstract: In an FM stereo receiving device according to the present invention, a received first FM-modulated wave is demodulated by means of an FM-demodulator, from the demodulated output of which a subcarrier signal is produced, further a monaural signal is extracted by means of an LPF, and the monaural signal is again FM-modulated by means of a voltage controlled oscillator to obtain a second FM-modulated wave. Then a difference frequency component wave is produced by a multiplication operator and an LPF, starting from the first FM-modulated wave and the second FM-modulated wave and the FM-modulated wave and the difference frequency component wave are switched over with the subcarrier signal by means of a switch circuit. In this way signals of a right ear side component and a left ear side component are obtained and a stereo signal is obtained by FM-demodulating both the signals by means of the FM-demodulator.

Abstract: Repetitive phenomena cancelling controller arrangement for cancelling unwanted repetitive phenomena comprising known fundamental frequencies. The known frequencies are determined and an electrical known frequency signal corresponding to the known fundamental frequencies of the unwanted repetition phenomena is generated. A plurality of sensors are employed in which each sensor senses residual phenomena and generates an electrical residual phenomena signal representative of the residual phenomena. A plurality of actuators are provided for cancelling phenomena signals at a plurality of locations, and a controller is utilized for automatically controlling each of the actuators as a predetermined function of the known fundamental frequencies of the unwanted repetitive phenomena and of the residual phenomena signals from the plurality of sensors.

Abstract: A decoding arrangement for decoding audio signals previously encoded in accordance with the dbx format, includes a wideband expander instead of a full dbx expander. The wideband expander employs a relatively simple, and therefore inexpensive, peak detector in place of the true RMS detector of a full dbx expander, and does not include apparatus for spectral expansion of the audio signal. Although the decoding is noncomplementary with respect to the encoding, the stereo audio reproduction as perceived by a listener, is surprisingly good.

Abstract: A first amplifier is configured for accepting a signal input and providing a drive signal to a load. A second amplifier is configured in a voltage follower configuration with an input derived from the output of the first amplifier. The output of the second amplifier is coupled in parallel with the first to the load. The output from the second amplifier is nearly an exact duplicate of the output from the first amplifier, and the output contributions from the two amplifiers are therefore substantially equal. Isolation resistors are provided in series with the load and the respective output terminals of the amplifiers for protecting the operational amplifiers from adverse loading conditions.

Abstract: A loudspeaker characterized by a symmetrical arrangement of planar mid-range and/or low-range drivers about an essentially point source tweeter. A flexible mounting of a speaker diaphragm to a rigid support serves to reinforce the advantages achieved thereby or is utilized independently, for instance to provide an improved sub-woofer.

Abstract: A sound field switcher inputs an output sound field signal from a sound field producer. The inputted sound field signal is delayed sequentially by plural delayers, after which they are multiplied by coefficients by plural multipliers, and the multiplied results are all added by an adder. Coefficients stored in an area of a memory indicated by a coefficient counter are read out and set to the plural multipliers. The sound field switcher carries out control of the timing for switching the sound field signal produced by the sound field producer and the timing for the coefficient counter to commence counting. Assuming the time required for switching the sound field to be N sampling periods, in case of carrying out a sound field switching from a sound field A to a sound field B, a sound field switching controller issues an order to the coefficient counter so as to count up one by one from 0 to N, and on each count the coefficients stored in an area of the coefficient memory is set to the multipliers.

Abstract: A noise reduction apparatus in an FM stereo tuner including a circuit for generating a stereo sum signal and a stereo differential signal; a noise eliminating circuit for dividing, in accordance with several frequency bands, the stereo differential signal into several divisional signals and for outputting, in accordance with signals levels corresponding to the frequency bands, a composite signal of divisional stereo differential signals respectively corresponding to the signal levels; and a circuit for reproducing a stereo signal from the composite signal and the stereo sum signal.