Abstract: The present invention is a digital dynamic compression or automatic gain control (AGC) (10) adapted for use in high quality audio and hearing aids applications. An efficient digital AGC design employs two compact ROM-based tables (ROM_CSD, ROM_SPL) in addition to two comparators (COMP_A, COMP_B) and several registers (REG_A, REG_B, ADDR_A, ADDR_B). While one ROM stores the values of discrete input signal levels, the other contains gain codes based on a canonical signed digit (CSD) coding approach that leads to a very simple gain multiplier (20). In many cases an extremely compact table for gain values can be achieved by reusing a single small-size ROM that behaves like one that is several time larger. Two design examples are shown to expound the insights of the new digital AGC design. For the less-than-half-dB-gain-step cases only two adders are required for the multiplier whereas just three adders are needed in the situations with less than quarter-dB gain steps.

Abstract: A sound processing system reduces the instances when only a center speaker is heard. The gain of a volume setting is adjusted for individual speakers in response to one or more input signals. The gain of the center speaker is attenuated in relation to the global volume setting. In addition or as an alternative, the gain of front and/or rear speakers is increased. A virtual center channel is generated for locations where the center speaker may not be heard.

Abstract: Stereo recovery circuitry for a digital receiver is disclosed that provides increased accuracy and efficiency in recovering stereo signal information from transmitted stereo signals. The stereo decoder includes a digitally controlled oscillator that recovers a pilot tone signal from transmitted stereo signal information. By processing demodulated stereo signals on the digital side and digitally controlling the oscillator, the stereo decoder has increased efficiency and accuracy. In one embodiment, the oscillator may be a phase-locked-loop having a loop filter and an amplitude stabilized tunable resonator. Additional circuitry is disclosed for utilizing the pilot tone signal to recover left and right channel signal information from the demodulated stereo signals.

Abstract: The invention provides an apparatus and related method for acoustically improving an environment. In an embodiment of the present invention, an electronic sound screening system includes a portion for receiving acoustic energy and converting it into electrical signals, a portion for performing an analysis of the electrical signals and for generating data analysis signals, a portion responsive to the data analysis signals for producing signals representing sound, and an output portion for converting the sound signals into sound.

Abstract: A system and method are described for rendering a left rear surround input signal at a left rear virtual speaker location and rendering a right rear surround input signal at a right rear virtual speaker location. The method includes phase shifting the left rear surround input signal by a first phase shift. The right rear surround input signal is phase shifted by a second phase shift. The phase shifted left rear surround input signal is phase shifted using an HRTF selected to render the left rear surround input signal at the left rear virtual speaker location. The phase shifted right rear surround input signal is transformed using an HRTF selected to render the right rear surround input signal at the right rear virtual speaker location.

Abstract: A sound processing system adaptively mixes active matrix decoding and passive matrix processing of incoming audio signals. Mixed output signals are generated with active matrix decoding where the audio signals are stereo. Mixed output signals are generated with passive matrix processing where the audio signals are monaural. The sound processing system reduces the degree of active matrix decoding in the mixed output signals where the incoming audio signals are stereo and monaural. The sound processing system also generates virtual stereo signals from incoming audio signals having monaural signals. Mixed output signals are generated of the virtual stereo signals using active matrix decoding.

Abstract: The invention concerns a method for transmitting in an area (100) information items in the form of sound waves representing a signal X(t), through a loudspeaker enclosure (2), said method comprising a step of setting up a public address system which consists in applying to the input of the loudspeaker enclosure (2) an electric signal P(t)=W(t) ?X(t) wherein is the convolution product and W(t)=S(?t)? I(t), wherein S(?t) is the temporal return of the pulse response S(t) between the enclosure and the target zone (101) belonging to the area to be fitted with a P.A. system (100) t representing time, and I(t) is the temporal response of the product e?2inft0.Sc (f), wherein f represents the frequency, t0 is a constant Sc(f)=1/(S1(f))?, ? being a non-null positive number and S1(f) being a real function obtained by peak clipping of the modulo I S(f) I of the frequency response S(f) of S(t).

Abstract: In a player/recorder system, a graphical user interface method allows central control of one or more tracks of a plurality of audio processing modules. The plurality of audio processing modules are connected to a computer system having a processor and a display. The method includes the steps of generating a first display portion on the display by the processor, the first display portion including one or more control boxes to control a corresponding one or more tracks of the plurality of audio processing modules and generating a second display portion on the display by the processor, the second display including a central control mechanism for controlling all of the one or more tracks of the audio processing modules.

Abstract: An audio converter device and a method for using the same are provided. In one embodiment, the audio converter device receives the digital audio data from a first device via a local area network. The audio converter device decompresses the digital audio data and converts the digital audio data into analog electrical data. The audio converter device transfers the analog electrical data to an audio playback device.

Abstract: An active noise attenuation system includes a speaker housing for a speaker assembly that attenuates noise generated by an air induction system for a vehicle engine. The speaker housing is a generic housing formed from plastic that can be utilized with many different vehicle types. An air cleaner housing is positioned between the speaker housing and the engine for filtering out contaminants from the air before the air is drawn into the engine. Brackets are joined to the air cleaner and speaker housings for mounting the housings to a vehicle structure.

Abstract: The invention relates to a method for reducing feedback caused by electromagnetic interference between an induction coil and an output transducer, a voltage supply or an amplifier or a combination thereof, the method comprising: producing by means of a filter an equivalent of an electromagnetic feedback path in a system with a pickup coil and subtraction of the equivalent of the feedback signal from the input signal in order to obtain feedback reduction. The invention further relates to a device for implementing the method, the device comprising an induction coil and an output transducer, voltage supply or an amplifier or a combination thereof. The device further comprises filter means for generating an equivalent of an electromagnetic feedgack signal occurring between the induction coil and an output transducer, a voltage supply or an amplifier or a combination thereof and means for subtracting the equivalent from an input signal in order to obtain feedback reduction.

Abstract: A circuit for processing an audio signal includes an input stage to which the audio signal is applied and an output at which the processed audio signal is presented. The circuit comprises first and second input stages (11, 12) having nonlinear performance curves, the first stage receiving the audio signal at a specified phase, and the second stage receiving from an inverter (13) an inverse phase of the audio signal. A positive half wave of the input signal is processed nonlinearly and the negative half wave is processed linearly. A difference amplifier (14) receives the signals produced by the first and second input stages and generates an audio signal representing a difference between the signals present at its inputs.

Abstract: An apparatus and method for controlling a plurality of speakers, comprising an amplifier for amplifying and outputting a play signal to be played over the speakers; and at least one sensor disposed proximal to at least one of the speakers for sensing at least one environmental condition and outputting sensing data to a controller, wherein the controller adjusts the play signal to compensate for environmental changes based on the sensing data.

Abstract: A method and apparatus for processing multi-channel audio signals in which the channels are processed by one of alternatively selectable processes to produce an alternatively selectable number of output channels, the process being responsive to information contained in the input signal.

Abstract: The present invention relates to methods and devices for processing one or the other of two types of common input audio stereo signals so that the output signals will reproduce normally wide stereo sound from an audio stereo reproduction system comprising a pair of identical loudspeakers positioned adjacent or close to each other. Thus, the invention relates partly to a method and a device for producing that specific pair of left and right output signals from one kind (M+S) of input signals, and partly to a method and a device for producing a similar type of left and right output signals from another kind (L+R) of input signals. Finally, the invention relates to an audio stereo signal reproduction system comprising a pair of identical louspeakers positioned adjacent or close to each other and intended for reproduction of normally wide stereo sound from one (M+S) of said kinds of input signals.

Abstract: This invention is a circuit that actuates a loudspeaker at input frequencies above a predetermined threshold and mutes the loudspeaker at input frequencies below the threshold. The circuit includes a comparator that generates a pulse train proportional in frequency to an input audio signal. The pulse train is then coupled to a flip flop array. The flip flop array is controlled by a clock having a specified frequency and duty cycle. The clock, in conjunction with the particular number of flip flops, creates a time window in which pulses may pass. The output of the flip flop array is coupled to an enable input of an audio amplifier. When the frequency of the pulse train is great enough to allow a number of pulses equal to or greater than the number of flip flops to pass within the window, the loudspeaker is actuated. Below this frequency, the loudspeaker is muted.

Abstract: An audio converter device and a method for using the same are provided. In one embodiment, the audio converter device receives the digital audio data from a first device via a local area network. The audio converter device decompresses the digital audio data and converts the digital audio data into analog electrical data. The audio converter device transfers the analog electrical data to an audio playback device.

Abstract: An audio converter device and a method for using the same are provided. In one embodiment, the audio converter device receives the digital audio data from a first device via a local area network. The audio converter device decompresses the digital audio data and converts the digital audio data into analog electrical data. The audio converter device transfers the analog electrical data to an audio playback device.

Abstract: Systems, devices, and methods are provided to inhibit apparent amplitude modulation in non-linear processing that causes distortion in a processed signal. One aspect of the invention includes a hearing aid. The hearing aid includes a microphone to receive an input signal, a speaker to reproduce the input signal, and a processor. The processor processes the input signal using a gain. The processor includes an inhibitor, which inhibits distortions, and an adjuster, which adjusts the gain. The inhibitor acts to smooth an envelope of the input signal to inhibit undesired modulation. The adjuster adjusts the gain if the envelope is either above or below a threshold. The hearing aid further includes a compression recapture system to supply the compressed portion of the input signal to more closely reproduce the actual input signal.

Abstract: A method for the visualization of the hearing capacity of a person. As a function of audiogram data, text is modified in any of several characteristics, including brightness, contrast, sharpness, and/or omission of letters.