Abstract: A multi-channel audio playback apparatus including a channel interface, a first switching amplifier and a second switching amplifier is provided. The channel interface is used to receive multi-channel digital data and generate first channel digital data and second channel digital data. The first switching amplifier is used to convert the first channel digital data into a first pulse width modulation (PWM) signal according to a first reference signal with a first frequency. The second switching amplifier is used to convert the second channel digital data into a second PWM signal according to a second reference signal with a second frequency. The second frequency is different from the first frequency.

Abstract: Characteristic amounts in each small region of audio signals transmitted in the working system and the standby system are extracted by characteristic amount calculators 6-1, 6-2. A characteristic amount comparator 7 compares the characteristic amounts and judges occurrence of a fault. Characteristic amount difference calculators 9-1, 9-2, ?D? comparator 10, and faulty system judging unit 11 judges the system having a fault. Majority decision processor 12 and significance judging unit 13 enhance the reliability of the judgment. Delay difference of audio signals between systems is roughly detected by sub-sampling audio signals of two systems and comparing them, and then accurately detected without sub-sampling. Delay difference between audio signals is adjusted by the detected delay difference.

Abstract: The invention relates to a system and method for transmitting audio data in a combined cabin management system in an aircraft with the steps: playing back entertainment programs and providing communications possibilities with an entertainment system (1), which is connected to several first audio data sources (3) and to several first audio playback devices (4), setting and displaying cabin parameters with a control system (2), which is connected to several second audio data sources (8) and to several second audio playback devices (9), transmitting audio data between the control system (2) and the entertainment system (1) with several audio channels (6) each with a coding device (5) and a decoding device (7) respectively.

Abstract: A system and method for minimizing the complex phase interaction between non-coincident subwoofer and satellite speakers for improved magnitude response control in a cross-over region. An all-pass filter is cascaded with bass-management filters in at least one filter channel, and preferably all-pass filters are cascaded in each satellite speaker channel. Pole angles and magnitudes for the all-pass filters are recursively calculated to minimize phase incoherence. A step of selecting an optimal cross-over frequency may be performed in conjunction with the all-pass filtering, and is preferably used to select an optimal cross-over frequency prior to determining all-pass filter coefficients.

Abstract: There are provided connectors in a main box that selectively outputs an audio signal from source units to zone units and successively updates a program of the zone units by an update data input via the connectors.

Abstract: A method and apparatus for processing an audio signal is disclosed. Herein, the method includes receiving a downmix information having at least two independent objects and a background object downmixed therein; separating the downmix information into a first independent object and a temporary background object using a first enhanced object information; and extracting a second independent object from the temporary background object using a second enhanced object information.

Abstract: Disclosed are systems and methods for wirelessly recording multi-track audio files without the data corruption or loss of data that typically occurs with wireless data transmission. In some aspects of the present invention, each performer is equipped with a local audio device capable of locally recording the respective performer's audio while also transmitting it to a master recorder. The locally recorded audio may then be used to repair or replace any audio lost or corrupted during transmission to the master recorder. Such repair or replacement may be performed electronically or via playback of the locally recorded audio. In other aspects of the present invention, a master recorder is not required since all locally recorded audio may be combined or otherwise processed post-recording. A multi-memory unit is provided in another aspect of the present invention to facilitate manipulation and processing of audio files.

Abstract: In one aspect, the invention divides an audio signal into auditory events, each of which tends to be perceived as separate and distinct, by calculating the spectral content of successive time blocks of the audio signal (5-1), calculating the difference in spectral content between successive time blocks of the audio signal (5-2), and identifying an auditory event boundary as the boundary between successive time blocks when the difference in the spectral content between such successive time blocks exceeds a threshold (5-3). In another aspect, the invention generates a reduced-information representation of an audio signal by dividing an audio signal into auditory events, each of which tends to be perceived as separate and distinct, and formatting and storing information relating to the auditory events (5-4). Optionally, the invention may also assign a characteristic to one or more of the auditory events (5-5).

Abstract: An integrally mounted control point node for use in an audio distribution system and including a control processor for receiving command signals and providing audio control signals to response thereto; a command signal generator for producing the command signals in response to activation by a user of the system; a terminal for receiving a plurality of audio signals; an audio signal tuner for receiving the control signals and the audio signals; an amplifier receiving an output signal from the tuner and the control signals from the control processor; and a speaker terminal for transmitting the output signal to a speaker.

Abstract: A measurement system and method combine an audio announcement system with a plurality of spaced apart sensors to evaluate intelligibility of audio output from loudspeakers of the audio announcement system. Processing can take place at some or all of the sensors as well as at a common control element. Evaluations can be based on use of an appropriate speech intelligibility index method.

Abstract: This invention concerns a distributed stereo audio system. Distributed stereo audio systems are used to provide stereo sound to several rooms or areas from a single source of signal. The system includes two or more speakers for the broadcast of stereo audio signals; a source of stereo audio signals; a stereo amplifier to amplify stereo audio signals and drive the speakers; and a mains operated electrical power supply to provide power to the amplifier. The amplifier is located in the same room as the speakers, and remote from the signal source and power supply. The amplifier is connected to the signal source and power supply by means of a category 5 four pair twisted cable which provides, in respective twisted pairs, right channel audio signals from the signal source to the amplifier, left channel audio from the signal source to the amplifier, DC power from the power supply to the amplifier, and control signals from the amplifier to the signal source.

Abstract: A microphone bar for obtaining audio input for a video conferencing system includes a master module and one or more slave modules. The master module houses a first pair of unidirectional microphones for obtaining audio from opposite sides of the bar, and each of the slave modules houses a second pair of unidirectional microphones for obtaining audio from opposite sides of the bar. Extensions connect the modules together, and at least one bus conducts audio signals through the extension from the microphones to the video conferencing system. The microphones are operable according to a broadside mode of stereo operation when a central axis of the bar is substantially orthogonal to a view angle of the conferencing system. Furthermore, the microphones are operable according to an end-fire mode of stereo operation when the central axis of the bar is substantially parallel to the view angle of the conferencing system.

Abstract: A communication system has a communication controller for multiplexing and transmitting a power supply voltage and an audio signal to be played back by a plurality of channels, and a plurality of communication adapters which start in response to reception of the multiplexed/transmitted power supply voltage, and play back the audio signal using a playback device. The communication controller includes an audio data modulation circuit configured to modulate audio data by shifting, based on a first modulation ratio, a modulation carrier clock for modulating the audio data and a data transmission rate for transmitting the audio data in order to set a command transmission frequency bandwidth, and a command data modulation circuit configured to modulate command data by shifting, based on a second modulation ratio, a modulation carrier clock for modulating the command data and a data transmission rate for transmitting the command data in the command transmission frequency bandwidth.

Abstract: The invention relates to sonic steerable antennae and their use to achieve a variety of effects. The invention comprises a method and apparatus for taking an input signal, replicating it a number of times and modifying each of the replicas before routing them to respective output transducers such that a desired sound field is created. This sound field may comprise a directed beam, focus beam or a simulated origin. Further, “anti-sound” may be directed so as to create nulls (quiet spots) in an already existing sound field. The input signal replicas may also be modified in way which changes their amplitude or they may be filtered to provide the desired delaying.

Abstract: An audio accessory for a headset. The accessory includes a first circuit for wirelessly receiving audio signals from a first external source of audio signals, a second circuit for mechanically coupling to a second external source of audio signals for receiving the audio signals from the second external source of audio signals, controlling circuitry for controlling the relative amplitude of audio signals from the first external source and the second external source transmitted to a playback device, a connector for detachably coupling to the playback device to transmit audio signals from the controlling circuitry to the playback device, and circuitry communicatingly coupling the controlling circuitry and the connector for transmitting audio signals from the controlling circuitry to the connector.

Abstract: A wireless headphone device may include a receiver for receiving a wireless digital signal containing a plurality of digital audio streams combined with control codes according to a predetermined format, a manually operated selector switch for selecting one or more of the plurality of digital audio streams to be produced as audio for the user, and a decoder for extracting the selected audio streams from the received signal in accordance with the predetermined format and for responding to the control codes in the received signal to perform predetermined functions.

Abstract: A stereo audio signal is processed to determine primary and ambient components by transforming the signal into vectors corresponding to subband signals, and decomposing the left and right channel vectors into ambient and primary components by matrix and vector operations. Principal component analysis is used to determine a primary component unit vector, and ambience components are determined according to a correlation-based cross-fade or an orthogonal basis derivation.

Abstract: An audio apparatus includes a main unit to extract audio signals for at least two channels from a multichannel audio signal; and a transmitter to wirelessly transmit at least one audio signal of the extracted audio signals to a first receiver, and to wirelessly transmit at least one other audio signal of the extracted audio signals to a second receiver.

Abstract: The invention relates to sonic steerable antennae and their use to achieve a variety of effects. The invention comprises a method and apparatus for taking an input signal, replicating it a number of times and modifying each of the replicas before routing them to respective output transducers such that a desired sound field is created. This sound field may comprise a directed beam, focus beam or a simulated origin. Further, “anti-sound” may be directed so as to create nulls (quiet spots) in an already existing sound field. The input signal replicas may also be modified in way which changes their amplitude or they may be filtered to provide the desired delaying.

Abstract: An audio system, an audio apparatus, and a method for performing audio signal output processing are provided that prevent the occurrence of sound interruption of high-priority voice signal output, such as voice guidance for navigation. The audio system includes the audio apparatus communicatively connected to an electronic device for producing an audio signal and to an electronic device for producing a high-priority voice signal (voice guidance signal). When the voice guidance signal is received with the audio signal being received, the audio apparatus starts to perform a mixing operation of the voice guidance signal. If a request for switching a sample rate of the audio signal is made during the mixing operation, the audio apparatus suspends a sample-rate switching operation until the mixing operation is completed.

Abstract: An audio signal receiving apparatus includes a sound source information receiving portion to receive sound source information containing sound source type information indicating a sound source type of the audio signal being transmitted through channels and externally connected equipment playback sound source information indicating a sound source type of the audio signal being played back by the externally connected equipment from externally connected equipment, an audio signal receiving portion to receive the audio signal from the externally connected equipment, and a playbackable sound source setting portion to determine and set a sound source type of the audio signal that can played back to a playbackable sound source based on the sound source information. The playbackable sound source setting portion sets a sound source type of the audio signal being played back by the externally connected equipment to the playbackable sound source as an externally connected equipment playback sound source.

Abstract: A single control determines both volume and the degree of compression in the reproduction of motion picture soundtracks. For some settings of the control, compression or limiting reduces the highest levels on a movie soundtrack, leaving the dialogue level substantially unchanged, thus removing the reason for complaints from the audience without the danger of making the dialogue too quiet for intelligibility.

Abstract: Provided are a method and apparatus for controlling a sound field through an array speaker. The method includes calculating a coefficient of a filter that controls sound pressure of an input signal, based on a sound pressure ratio of a suppression area that suppresses sound emitted from an array speaker and an emphasis area that emphasizes the sound, and sound pressure efficiency in the emphasis area, generating a plurality of output signals that focuses the sound to the emphasis area by filtering the input signal based on the calculated coefficient of the filter, and outputting a sound field controlled sound based on the generated plurality of output signals. Accordingly, a listener in a predetermined direction and distance from the array speaker can clearly hear sound, without wearing an earphone or a headset so as to focus the sound only to the listener.

Abstract: The appliance comprises an audio port, which is usable as an interface for testing of the appliance. In a preferred embodiment, the appliance comprises stereo output ports, one port for a reception of digital test signals from a control computer and the other port for a transmission of digital signals from the appliance to the control computer. For the separation of the test signals and the audio signals a test adapter is used which is coupled between the appliance, the control computer and an amplifier for the audio signals. The test signals are modulated onto a carrier signal having a frequency of above 20 kHz, for example a frequency within the frequency range of 1-10 MHz. This allows a serial connection, which is compatible with the widely used RS232 link for set-top boxes.

Abstract: The present invention relates to sharing of content between multiple users. A data player(10) decodes pre-stored audio data therein using a decoding function, and a converter converts the decoded digital data to analog to a headphone set in communication with the data player. When another user places his or her headphone set (2,4) close to the data player(10), the data player(10) confirms whether it has right to receive transmission from the data player, and after successful verification, reproduced data from the data player can be shared by the users.

Abstract: A media application for providing outputs (e.g., audio outputs) in response to inputs received from an input device is provided. The media application may connect input mechanisms of an input device with parameters of channel strips (e.g., which may define output sounds) using an intermediate screen object. The media application may first assign an input mechanism to a screen object, and separately map a screen object to a channel strip parameter. The media application may map a screen object to several channel strips simultaneously such that, based on the value of the screen object, the volume of each of the several channel strips changes. The media application may provide a graphical representation of available channel strips using layers. As the media application accesses a channel strip, the appearance of the portion of the layer associated with the channel strip may change.

Abstract: According to the invention, there is provided an audio signal receiving apparatus which receives audio signals transmitted from external connection apparatuses through a plurality of channels, including an audio signal transmitting scheme determining unit which determines a transmitting scheme of the audio signal in the external connection apparatus on the basis of channel mapping information representing types of the audio signals transmitted by the external connection apparatuses. When the audio signal to be received is changed, a process to be executed is changed depending on the transmitting scheme of the audio signal.

Abstract: A system is provided for receiving audio signals from a plurality of microphones and transferring the audio signals via a common composite signal channel to a receiving unit, such as a mixing console. The system has at least two satellite units, each having a microphone signal input, a composite signal channel input and summing means for summing a microphone signal and a composite signal. The system further has a master unit with a composite signal channel input, and signal converting means for converting said composite signal into a master signal, which is provided to the receiving unit via a master signal output. In the system, each satellite unit is connected to the common composite signal channel, such that the microphone signal received at the respective satellite unit, is added to the composite signal, which is fed to the master unit.

Abstract: A method and system for communicating audio, video, and/or control signals within a home entertainment system. A plurality of audio channels is communicated between a wireless transmitter and a wireless receiver. The wireless transmitter is located proximate to a speaker housing. In some embodiments the speaker housing also encloses a center channel loudspeaker. The center channel loudspeaker transmits an audio signal to a remote loudspeaker. An exemplary remote loudspeaker is a subwoofer loudspeaker. The subwoofer loudspeaker provides one or more received audio channels to one or more surround loudspeakers.

Abstract: A routing screen is presented on an electronic device by a user interface application in response to receiving a notification that an external audio device is connected to the electronic device. The routing screen displays representations of an internal audio device and the external audio device. In one aspect, the representations are buttons. In another aspect, the representations are entries in a list. If a user selects one of representations, the user interface application causes the audio signals to be routed to the audio device represented by the selection. An application control screen having a set of objects that represent functions for an audio application may also be displayed. One of the objects on the application control screen is modified in response status changes in the external audio device. A user may select this object to access the routing screen when the external audio device is connected.

Abstract: A multi-accessory vehicle audio system is providing that includes a plurality of vehicle audio accessories, the vehicle audio accessories generating a corresponding plurality of audio signals; and an audio switching device. The audio switching device includes an input section for receiving the audio signals from the vehicle audio accessories, a switching section operatively coupled to the input section for receiving the audio signals, a controller operatively coupled to the input section for receiving the audio signals and operatively coupled to the switching section for providing control signals to control the switching section and to regulate the output of the audio signals from the switching section according to an instruction set, and an output section operatively coupled to the switching section for receiving the regulated audio signals outputted from the switching section.

Abstract: A method and system are provided for generating one or more mix coefficients for downmixing a multichannel input signal having a plurality of input channels, to an output signal having a plurality of output channels. Mix coefficients may be generated responsive to a comparison of energy between the downmixed (output) signal and the input signal to the downmixer, such that energy and intended direction of the input signal are substantially preserved in the output signal. Further, or in the alternative, the mix coefficient generation may preserve an intended direction of an input signal, for example, received at a surround input channel, in at least one output channel of the output signal. The mix coefficient values may be generated in a test downmixer environment. Additionally, one or more mix coefficients may be generated by retrieving predetermined mix coefficient values.

Abstract: A subwoofer (72) is equipped with a wireless receiver (80) to receive signals containing information for a Low Frequency Effects (LFE) channel and information for both surround channels. In one form, the LFE is added to one or both surround channels to provide a stereo surround signal (containing both surround channels including a multiplexed LFE channel). The subwoofer (72) utilizes the LFE channel, powers surround speakers (74, 76), and passes the surround signals to respective surround speakers. A receiver (66) multiplexes LFE signals into either one or both surround sound audio channels. A digital RF transmitter (70) of the receiver transmits the combined subwoofer/surround channels to the wireless receiver (80) of the subwoofer. The remote subwoofer is connected to a power source (78). The surround speakers (74, 76) are connected to the subwoofer so as to receive the surround channels and be powered thereby.

Abstract: An audio signal delivery management system includes a management apparatus and an delivering apparatus which delivers an audio signal to a plurality of speaker devices to which respective addresses are assigned. The delivering apparatus include an address storing portion which stores the addresses of the speaker devices, an audio signal acquiring portion which acquires an audio signal, an audio signal delivering portion which delivers the audio signal to at least one of the speaker devices using the addresses, and a sending portion which sends the audio signal to the management apparatus.

Abstract: An audio system responsive to a source of audio programming. The audio system comprising a master amplifier connected to the source of audio programming, the master amplifier providing channelized amplified audio signals at each one of a plurality of channel output connectors and a signal splitter connected to at least one of the plurality of channel output connectors for splitting the channelized amplified audio signal at a selected one of the plurality of channel output connectors into an audio channel signal and a power signal. The audio system further comprising a channel transmit module responsive to the audio channel signal and the power signal for transmitting the audio channel signal, a channel receiver responsive to an intended audio channel signal, a channel amplifier connected to an associated channel receiver for amplifying the intended audio channel signal and a sound reproducing device connected to the channel amplifier for aurally reproducing the intended audio channel signal.

Abstract: A spectator broadcast system includes a transmitter for broadcasting over one or more broadcast channels and a light weight ear mounted receiver for selectively receiving one or more broadcast channels. The receiver comprises a radio circuit, a speaker, control means comprising an on/off function and volume control, a power source, a channel selector switch and a semi-transparent case adapted to mount comfortably over the ear of a wearer by means of an ear hanging member. A light source is included to illuminate the case. In another embodiment spread spectrum technology is used. The system is adapted to broadcast over distances and at power levels permitted by the authorities.

Abstract: A method of restoring a corrupted audio signal comprises the steps of; inputting the corrupted audio signal in a first channel (30-32), inputting one or more further correlated audio signals in one or more further channels (33-35), and restoring the corrupted audio signal (36) using a Multi-Channel Autoregressive (AR) Model that models the corrupted signal as a linear combination of scaled time shifted portions of the further signal (s) and the corrupted signal. Embodiments are described in which the method is used to improve received audio signals in DAB receivers and mobile telephones.

Abstract: A wireless audio distribution system may have a wireless transmitter, responsive to a plurality of audio input channels, for transmitting signals carrying the audio, a receiver, responsive to the transmitted signals for selecting one or more of the audio input channels to be reproduced in accordance with local setting selectors at the receiver. An additional audio source, such as a microphone, can be selectively used by for example the driver to talk on the cell phone or to make announcements to passengers via the wireless audio distribution system in accordance with a master settings selector which may be used to override local settings such as audio channel or volume selection.

Abstract: In operation of an electronics device, audio based on asynchronous events, such as game playing, is intelligently combined with audio output nominally generated in a predictive manner, such as resulting from media playback. For example, an overall audio output signal for the electronic device may be generated such that, for at least one of audio channels corresponding to predictive manner processing, the generated audio output for that channel included into the overall audio output signal is based at least in part on configuration information associated with a processed audio output signal for at least one of the audio channels corresponding to asynchronous events based processing. Thus, for example, the game audio processing may control how audio effects from the game are combined with audio effects from media playback.

Abstract: An audio player capable of allowing multiple persons to listen to different multimedia files simultaneously is provided. The audio player includes a processing unit and a plurality of output channels. Each of the output channels is configured for outputting multimedia files. Each of the output channels includes a codec, an amplifier, and an audio output port. The amplifier is connected to the codec and the audio output port. The processing unit is connected with the output channels. The processing unit is configured for establishing a plurality of processes and for controlling performance of the processes according to time division multiplexing (TDM) technology. Wherein, each of the processes is configured for playing multimedia files and is assigned with one of the output channels for outputting the multimedia files.

Abstract: A communication system has a controller for transmitting data to be played back by a plurality of playback devices corresponding to a plurality of channels, and a plurality of adapters required for executing playback by the playback devices. The controller has a setting unit which sets data to be played back by the playback devices and control information required to control playback of the data in time slots of a sync transmission frame, and a transmission unit which transmits the sync transmission frame the by the setting unit to the adapters. Each adapter has a reception unit which receives the transmitted sync transmission frame, and a playback control unit which extracts data corresponding to the channel to be played back by the adapter from the sync transmission frame, and controls the playback timing of the data based on control information corresponding to the data.

Abstract: The invention relates to loudspeaker systems or loudspeaker columns as used in public address systems and at (pop) concerts. Such systems heretofore possess a frequency-dependent coverage angle and strong second and third order side lobes. The invention describes formulae of the voltage to be applied to the separate loudspeakers of the loudspeaker column, which makes it possible to realize the constant coverage angle over the entire frequency range and to suppress the side lobes to a far-reaching extent.

Abstract: An information source management system 11 performs inventory management for CDs and a material information management progress programming system 12 performs programming. An material information registration system 13 compresses the musical numbers of the CDs for holding on a proprietary server and a proprietary server 121 of a multi-channel sending-out system 101. A large number of materials are held on the proprietary server 121 and read out from it. The read-out materials are converted in its format to a transmission format by a sending-out server 123 so as to be multiplexed by a multiplexer 141. The multiplexed data is QPSK-modulated by a modulator 142 and sent out via a selector 143. From the proprietary server 121 are read out data which is sent out via dedicated network 3 to a live PC where it is reproduced. This data is furnished again via dedicated network 3 and encoded by an MPEG encoder 129 so as to be sent out at the sending-out server 123.

Abstract: Appropriate content is determined from among multiple content items, and is reproduced. Content reproduction terminal devices having the content items recorded therein are connected with a content reproduction controlling apparatus. An acquiring unit acquires content information from each content reproduction terminal device, information indicative of the subject matter of the content items. A determining unit determines the content items to be reproduced, i.e., reproduction content based on the acquired content information. An extracting unit extracts the reproduction content from the content reproduction terminal device that has the reproduction content recorded therein. A reproducing unit reproduces and outputs the extracted reproduction content.

Abstract: A system and method for generating, transmitting and distributing audio signals. The system and method may include an array having a plurality of microphones and a plurality of speakers as well as a first processor disposed proximate the array. The system and method can also have a second processor disposed remotely from the array and communicatively coupled with the array, at least one remotely located device having at least one microphone and at least one speaker and one or more remotely located speakers. Also, there may be an audio signal that is generated by one of a microphone on the array and a microphone on the at least one remotely located device, the location of the generation of the audio signal determined by one of the first processor and the second processor, generated audio signal transmitted to at least one of the speakers on the array, the at least one speaker on the remotely located device and the one or more remotely located speakers.

Abstract: A wireless audio distribution system may include a wireless transmitter transmititing an encoded digital bitstream serially combining each of a plurality of audio input channels and control data, a wireless receiver receiving the transmitted bitstream, a manual selector switch to for selecting one or more of the audio input channels and a sound producing device reproducing the selected audio channels in accordance with the control data. A system may include a wireless receiver receiving an encoded digital bitstream combining each of a plurality of audio input channels with control data disbursed therein, a manual selector switch for selecting audio input channels and a sound producing device for selectively decoding and demultiplexing the selected audio channels to be reproduced in accordance with the control data.

Abstract: A audio codec includes a first analog to digital converter for producing a first one-bit data stream, a second one-bit data stream is received from a digital microphone. A selection module produces a one-bit output signal that is the first one-bit data stream when a selection signal is in a first state, and produces a the one-bit output signal that is the second one-bit data stream when the selection signal is in a second state. A decimation and filter module produces a down sampled signal based on the one-bit output signal.

Abstract: A sound-amplification apparatus comprises: an acoustic signal source for outputting an acoustic signal; an amplified sound source for receiving the acoustic signal from the acoustic signal source and radiating an amplified sound; a control sound source provided in a vicinity of the amplified sound source for radiating a control sound; and signal processing means for producing a control sound signal by controlling at least one of an amplitude and a phase of the acoustic signal from the acoustic signal source so that an acoustic space having a desired directionality is formed by interference between the amplified sound and the control sound, and providing the control sound signal to the control sound source.

Abstract: This invention concerns a distributed stereo audio system (1). Distributed stereo audio systems are used to provide stereo sound to several rooms or areas from a single source of signal. The system includes two or more speakers (2, 3) for the broadcast of stereo audio signals; a source of stereo audio signals; a stereo amplifier (4) to amplify stereo audio signals and drive the speakers; and a mains operated electrical power supply (10) to provide power to the amplifier. The amplifier is located in the same room as the speakers, and remote from the signal source and power supply. The amplifier is connected to the signal source and power supply by means of a category 5 four pair twisted cable (11) which provides, in respective twisted pairs, right channel audio signals (12) from the signal source to the amplifier, left channel audio (13) from the signal source to the amplifier, DC power (14) from the power supply to the amplifier, and control signals (20) from the amplifier to the signal source.

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).