Abstract: A stereophonic processing system provided with spatial expansion of the stereophonic sound so that a pair of spaced-apart loudspeakers will acoustically appear to be spaced apart further then they actually are. The spatial expansion circuit includes tonal compensation.

Abstract: An acoustic signal reproduction device includes a reproduction speaker and a signal processing section for generating an acoustic signal for causing a listener to recognize a reference speaker. The signal processing section includes a compensation data input section for receiving compensation data from the outside of the acoustic signal reproduction device and a calculation section for calculating the acoustic signal based on the audio signal and the compensation data and outputting the acoustic signal to the reproduction speaker. The compensation data has a value H/C, where H is a transfer function from the reference speaker to a control point located in the vicinity of an ear of the listener, and C is a transfer function from the reproduction speaker to the control point located in the vicinity of the ear of the listener.

Abstract: Described is a personal on-demand audio entertainment system with a base unit attached to a personal computer or other source, a headphone unit and a remote control unit. The base unit transmits digital audio content to the headphone unit using infrared, radio frequency, magnetic or electromagnetic coupling. These data are stored in solid-state memory within the headphone unit. In the headphone unit, the stored digital audio content is converted to analog audio signals, amplified and sent to transducers for conversion to audio signal for the listener during playback. The system is designed such that playback may occur during the downloading process. The remote control unit also uses infrared, radio frequency, magnetic or electromagnetic coupling for communication to the headphone unit. This communication is made using a different channel and does not interfere with the audio data downloading.

Abstract: A digital audio decoder decodes or expands compressed data such as bit stream data, which are compressed based on the MPEG/Audio standard. Inverse quantization circuits perform inverse quantization on plural bit stream data, which are supplied thereto in connection with multiple channels respectively, thus producing inversely quantized data with respect to a prescribed number (e.g., thirty two) of sub-band samples respectively. The inversely quantized data are combined together among the multiple channels with respect to the prescribed number of the sub-band samples respectively. Then, a filter bank synthesizes together combined data corresponding to all of the sub-band samples, thus reproducing original digital audio signals. Multipliers are provided for use in gain control on the inversely quantized data with respect to the sub-band samples respectively.

Abstract: A monaural and stereo audio signal control system for use in cable-signal set-top boxes selects signal processing paths as a function of the monaural and stereo nature of the incoming audio component of the television signal and an indication as to whether the audio component is a “clear” or “masked” signal. A clear audio signal is a signal that conforms to a NTSC or BTSC standard that can be processed by a conventional television receiver while a “masked” signal is one in which the carrier frequency has been changed or otherwise modified so that a conventional television receiver cannot extract the audio content. A signal-processing path is provided for conventional clear monaural and stereo audio and for a masked monaural signal and for a masked stereo signal.

Abstract: The invention relates to a method for synthesizing a virtual sound source in a system (40) which comprises at least a right and a left channel for transmitting a stereo signal and in which the channels are connected to a filter block (42) for expanding the sound image. In the method, the amplifications of the separated monophonic and stereophonic signal components are optimized according to the stereophony of the signal coming to the system. The method according to the invention can also be applied to producing early room reflections by means of a separate filter block (71). The invention also relates to a device for synthesizing a virtual sound source, which device comprises at least a first and a second channel for transmitting the signal, at least one amplifier and filter and means for estimating the stereophony of the signal, for determining the amplification coefficient of the filtered signal and for controlling the amplifier according to the calculated amplification coefficient.

Abstract: To facilitate direct conversion to digital form of an acoustic signal acting on the acoustic receptor of an acoustic receiver while satisfying requirements of dynamic range, noise and adequate quantization, the following is proposed: the acoustic receptor should be exposed to a counter-signal when the acoustic signal acts on it in such a way that the acoustic receptor is largely maintained in its rest state despite the action of the acoustic signal. The counter-signal is derived from the control variable of a control circuit which is a component of the acoustic receptor. The control variable contains the information on the acting acoustic signal. Any deviation of the receptor from its rest state immediately generates a digital “nought” or “one.

Abstract: A speaker box for a sport utility vehicle. The speaker box is pivotally mounted to the sports bar of the vehicle and can be selectively pivoted relative to the bar to a plurality of positions. In one position, the sound from the speakers of the speaker box is directed downwardly as in convention designs. However, unlike conventional designs, the speaker box and its sound can also be directed rearwardly of the vehicle for parties and other gatherings such as at campsites or on the beach. Further, the speaker box and its sound can be directed slightly forward toward the front of the vehicle if desired. In doing so, a saddle or cutout is provided in the middle of the speaker box so as not to unduly inhibit the driver's vision through the rear view mirror.

Abstract: An intra-vehicle communication system includes a surface configured to be mounted to a vehicle interior proximate a first occupant wherein the surface is further configured to display an image of a second occupant of the vehicle. The system further includes an intercom including a microphone supported in close proximity with the surface and a speaker operably coupled to the microphone. In one embodiment, the intercom is further configured to at least partially mute existing audio output from a stereo system.

Abstract: An earset including a housing positionable with respect to an ear of a person, a microphone disposed with respect to the housing for insertion into the ear of a person, the microphone operable to detect a change in air pressure within the ear while the person speaks and to produce an electrical microphone signal corresponding to the internally detected change in air pressure and a speaker disposed with respect to the housing and operable to produce a sound corresponding to an electrical speaker signal. The earset also includes a circuit coupled to receive the microphone signal and the speaker signal and operable to produce a corrected microphone signal having a reduced feedback component of the microphone signal, the feedback component resulting from the detection by the microphone of the sound produced by the speaker to produce a corrected microphone signal.

Abstract: Described is a device and method using an interactive process to improve the listening experience for a user of headphones or hearing aids. The system uses a sound source such as a PC or similar device. Programming of the headphone or hearing aid is accomplished using a process delivered by the sound source. The user is prompted to listen to various signals thereby testing the frequency response of each ear and headphone combination. Once the user testing is completed, individualized compensation coefficients are created to optimize the listening experience for the user. The coefficients would be downloaded to and stored within the hearing aids. Downloading could accomplished by wire or by wireless means such as infrared, radio frequency, magnetic or electromagnetic coupling. In headphone units, the compensation factors could be stored either within the headphones or maintained at the sound source.

Abstract: A digital graphic equalizer uses a predetermined number of equalizing bands each having a different center frequency, and the center frequencies span a predetermined audio bandwidth. For each equalizing band a minimum set of filters is provided. The filters have a predetermined linear uniform spacing between the gain of successive filters.

Abstract: Clicks in voice and music signals are removed by detecting and interpolating the click. The use of a permanently set threshold value above the peak value of the audio signal is known for detecting the clicks, and interpolation carried out on the basis of the sample values before and after a click is known for filling them in. Disadvantages of these methods are, on the one hand, that many clicks do not have a larger amplitude than the peak signal and therefore remain undetected, and, on the other hand, interpolation is a highly complex procedure and is limited to a maximum click density. The invention provides for an error signal (en) to be determined by adaptive filtering (AF). A sample value is designated as distorted in the input signal (xn) if the absolute instantaneous value in the error signal (en) exceeds a dynamically adapted threshold value.

Abstract: A motorcycle audio system characterized by a housing for receiving a conventional or specially-designed radio, compact disc and/or tape player, CB radio or combination thereof, which housing is mounted to the windshield assembly of a motorcycle and includes an upwardly-oriented speaker on each end thereof. In a preferred embodiment, the housing is chrome-plated and, along with the speakers and the enclosed radio, compact disc player and/or tape player, CB radio or combination thereof, is easily viewed for safety and can be removed from the windshield assembly of the motorcycle and re-attached thereto, as desired, to facilitate maintenance work on, and/or cleaning of, the motorcycle. In some motorcycles, the windshield assembly can be conventionally removed from the motorcycle with the mounted audio system in place and unplugged, for cleaning and/or maintenance purposes.

Abstract: A member for producing an audible sound in a vehicle including a speaker area having an upper surface and a lower surface, the speaker area being located on the member. A piezo bimorph is attached to the speaker area, the piezo bimorph including a first piezoelectric element attached to the upper surface of the speaker area, and a second piezoelectric element attached to the lower surface of the speaker area. An amplifier in electrical communication with the piezo bimorph, the amplifier supplying an electrical field to the piezo bimorph, the piezo bimorph causing the speaker area and the member to vibrate, causing an audible sound.

Abstract: A method and apparatus for automatically compensating a sound volume are disclosed. The method includes the steps of determining whether a channel conversion key and an audio input switching key are inputted, producing an energy of an audio signal when the channel conversion key is inputted, and comparing an energy value of the audio signal detected for a predetermined time period with an energy value obtained from a previous step thereof and compensating for as much volume as a difference obtained by the comparison. The method together with the apparatus considers a symmetrical characteristic of an audio signal, calculates a voice energy with regard to a half signal of the audio signal, converts the calculated signal to a simplified value, and automatically compensates for the volume accordingly, thereby removing redundant manual steps.

Abstract: The method and the apparatus specify that the acoustic useful signal is generated from a electrical useful signal, that an electrical listening signal determined by the acoustic useful signal and by an acoustic noise signal at the listening location be recorded, and from this the useful signal component contained therein be extracted. Then the useful signal component contained in the listening signal is compared with the listening signal itself, and the electrical useful signal is adapted in dependence on this.

Abstract: A headset has an earcup with front opening adjacent to an annular cushion formed with a plurality of openings facing the inside of the earcup that acoustically couples the earcup volume to the cushion volume. A driver is seated inside the earcup with a microphone adjacent to the driver. Active noise reducing circuitry intercouples the driver and microphone. An acoustic load that may comprise a wire mesh resistive cover and/or air mass adjacent the microphone is constructed and arranged to reduce the effect of resonances in the earcup volume.

Abstract: A noise-reducing resonant chamber sound pick-up for electronic stethoscopes is claimed. It consists of a resonating chamber (24) which acoustically preamplifies the selected frequencies of heart sounds, 50-150 hz, and bruits of breath or blood, 150-500 hz, while rejecting ambient sounds. A skin contact (34) has elastic foam support (14), whose rigidity is varied by varying the applied pressure, in order to select the preamplified band of sounds. The other side of the resonating chamber contains a sound transducer (10) largely encased in heavy malleable metal (12) that absorbs sound not coming from the chamber. A damping vent hole (26) shapes the band of preamplified sounds. The resulting superior signal-to-noise ratio permits two, small chambers to be used in a stereophonic chest piece little larger than that of a conventional stethoscope, with better amplification enabling examination through clothing or surgical dressing even in heavy persons.

Abstract: A second-order adaptive differential microphone array (ADMA) has two first-order elements (e.g., 802 and 804 of FIG. 8), each configured to convert a received audio signal into an electrical signal. The ADMA also has (i) two delay nodes (e.g., 806 and 808) configured to delay the electrical signals from the first-order elements and (ii) two subtraction nodes (e.g., 810 and 812) configured to generate forward-facing and backward-facing cardioid signals based on differences between the electrical signals and the delayed electrical signals. The ADMA also has (i) an amplifier (e.g., 814) configured to amplify the backward-facing cardioid signal by a gain parameter; (ii) a third subtraction node (e.g., 816) configured to generate a difference signal based on a difference between the forward-facing cardioid signal and the amplified backward-facing cardioid signal; and (iii) a lowpass filter (e.g.