Abstract: A frequency-domain upmix process uses vector-based signal decomposition and methods for improving the selectivity of center channel extraction. The upmix processes described do not perform an explicit primary/ambient decomposition. This reduces the complexity and improves the quality of the center channel derivation. A method of upmixing a two-channel stereo signal to a three-channel signal is described. A left input vector and a right input vector are added to arrive at a sum magnitude. Similarly, the difference between the left input vector and the right input vector is determined to arrive at a difference magnitude. The difference between the sum magnitude and the difference magnitude is scaled to compute a center channel magnitude estimate, and this estimate is used to calculate a center output vector. A left output vector and a right output vector are computed. The method is completed by outputting the left output vector, the center output vector, and the right output vector.

Abstract: An approach to forming output signals both permits flexible and temporally and/or frequency local processing of input signals while limiting or mitigating artifacts in such output signals. Generally, the approach involves first synthesizing prototype signals for the output signals, or equivalently characterizing such prototypes, for example, according to their statistical characteristics, and then forming the output signals as estimates of the prototype signals, for example, as weighted combinations of the input signals.

Abstract: An apparatus for generating a stereo output signal includes a manipulation information generator being adapted to generate manipulation information depending on a first signal indication value of a first input channel and on a second signal indication value of a second input channel, and a manipulator for manipulating a combination signal based on the manipulation information to obtain a first manipulated signal as a first output channel and a second manipulated signal as a second output channel. The combination signal is a signal derived by combining the first input channel and the second input channel. Furthermore, the manipulator is configured for manipulating the combination signal in a first manner, when the first signal indication value is in a first relation to the second signal indication value, or in a different second manner, when the first signal indication value is in a different second relation to the second signal indication value.

Abstract: An audio signal enhancing device, and a corresponding method of enhancing stereophonic signals, is provided which generates an enhanced signal with improved spatial sound image quality for upmixing a stereophonic input signal. When used in combination with a centre channel processor or LFE processor, an improved processing of the input signals is provided resulting in final centre channel and at least one LFE sub-woofer channel wherein the problems and disadvantages of the prior art are resolved. The result is a centre and LFE signal that contains a stable, non time-smeared image with a high quality natural-sounding fidelity. These advantages are achieved especially for time-delayed or phase-panned stereo input signals, independently of whether they are matrix encoded or non-matrix encoded input signals.

Abstract: A surround system includes a decoder that decodes an encoded audio data stream, a decorrelation unit that receives and decorrelates stereo signals decoded by the decoder so as to generate surround signals having a low-correlation component, an addition unit that adds high-correlation-component signals extracted from the stereo signals to the surround signals generated by the decorrelation unit, and a controller that controls addition of the high-correlation-component signals performed by the addition unit on the basis of the bit rate of the audio data stream.

Abstract: In accordance with some embodiments of the present invention there is provided a system, a method and a circuit for processing a stereo audio signal. According to some embodiments, the system for processing a stereo audio signal may include an audio processing circuit. The audio processing module or circuit may be operatively connected to an audio input interface and to an output audio interface. Through the audio input interface, the audio processing circuit may be adapted for receiving a 2-channels stereo audio signal. The audio processing module may be adapted for determining an output mono audio signal representing the center sound and a stereo audio signal representing the stereo sound without the center. Through the output interface the audio processing circuit may provide each of an output mono audio signal representing the center sound and a stereo audio signal representing the stereo sound without the center.

Abstract: A digital signal processing system and method transforms pairs of channels selected from a multichannel signal into the frequency domain. Vector operations are performed upon the frequency-domain data by which signal components unique to one of the input channels are routed to one of the output channels, signal components unique to the other of the input channels are routed to another of the output channels, and signal components common to both channels are routed to a third and optionally to a fourth output channel. The frequency-domain output channels are then transformed back into the time-domain, forming a plurality of time-domain output channels. The vector operations are performed in a manner that preserves the overall information content of the input data.

Abstract: There is provided a content reproduction apparatus including a reproduction request receiving unit that receives from a first external device conforming to a first communication standard a request to reproduce content data selected by the first external device, a content data obtaining unit that obtains from a second external device conforming to the first communication standard, which stores the content data selected by the first external device, the content data in response to the received request, a content reproduction unit that reproduces the obtained content data, and a data converting unit that converts data which can be transmitted according to the first communication standard into data which can be transmitted according to a second communication standard different than the first communication standard.

Abstract: A switching section causes the first amplification section to amplify the expansion left audio signal and supply the amplified expansion left audio signal to the first speaker terminal and causing the second amplification section to amplify the expansion right audio signal and supply the amplified expansion right audio signal to the second speaker terminal when the Bi-Amp function is not used. The switching section causes the first amplification section to amplify the left audio signal for Bi-Amp and supply the amplified left audio signal for Bi-Amp the first speaker terminal and causing the second amplification section to amplify the right audio signal for Bi-Amp and supply the amplified right audio signal for Bi-Amp to the second speaker terminal when the Bi-Amp function is used.

Abstract: An audio information processing apparatus for processing input audio information is adapted to input an audio signal composed of front area audio information that should be input to a front speaker and rear area audio information that should be input to a plurality of speakers. A mixer is adapted to mix the rear area audio information in accordance with an instruction from an instruction circuit.

Abstract: In an AV system in which a television apparatus and a recorder are individually connected to an AV amplifier through an HDMI, in the case where sound is output from the AV amplifier, if insertion of headphones into the television apparatus is detected, control information to switch the destination of the audio data is transmitted from the television apparatus to the AV amplifier. The AV amplifier switches the destination of the audio data that is input from the recorder from a speaker output section to the television apparatus in accordance with the control information. Thus, even if the headphones are inserted into the television apparatus while the AV amplifier is outputting sound reproduced by the recorder, the sound can be output from the headphones.

Abstract: A loudspeaker apparatus includes a speaker array that has a plurality of speaker units which are arranged on a sound emitting surface of the speaker array, and emits sound beams on a plurality of channels, an angle sensing section that senses an angle change displaced from a previously set reference angle of the sound emitting surface, and an adjusting section that adjusts output angles of the sound beams in response to the angle change.

Abstract: In a system capable of outputting an audio signal as beams from an array speaker and performing multi-channel reproduction, a plurality of beam setting patterns (reproduction modes) are stored in the memory of a controller. The beam setting patterns include a single basic pattern and a plurality of deformed patterns that use the beam control data of the basic pattern. When the user specifies a reproduction mode via an interface, the beam setting pattern corresponding to the mode is read and set to the signal processor of each channel.

Abstract: An audio output device includes: a main unit including a terminal configured to connect an external speaker; a speaker unit configured to be detachably attached to the main unit while the terminal is covered with the speaker unit; and an amplification unit configured to amplify an audio signal so that the amplified audio signal is input to the terminal and the speaker unit.

Abstract: A method of processing a 2-channel stereo sound signal into a spatial stereo sound includes generating stereo signals of first and second channels from a first input channel signal and a second input channel signal by applying a time difference of times taken for each channel signal to arrive at two ears, and a sound pressure difference formed between the two ears and varying with respect to a frequency band or constant, to each of the first and second input channel signals, generating a center channel of the first and second channel by adding the first and second input channel signals, generating a surround signal of the first channel by subtracting one of the first and second input channel signals, from the other one of the first and second input channel signals, and generating a surround signal of the second channel by making the surround signal of the first channel out of phase, generating a plurality of reflected sounds from the generated surround signals, and applying the time difference and the sound p

Abstract: In an audio signal processing device, a signal input part receives a plurality of audio signals to be provided to a plurality of speakers, respectively, arranged so as to surround a listener, the speakers including a center speaker, a left speaker and a right speaker. A signal processing part adds a processed audio signal to an audio signal to be provided to the center speaker, the processed signal being obtained by attenuating a summation of audio signals to be provided to the left speaker and the right speaker. The signal processing part attenuates the summation of the audio signals by an attenuation rate which is set between 0 and 1. The signal processing part sets the attenuation rate to an appropriate value effective to suppress crosstalk between sound emitted from the left speaker and sound emitted from the right speaker.

Abstract: An apparatus and method of reproducing a virtual sound of two channels which adaptively reproduces a 2-channel stereo sound signal reproduced through a recording medium such as DVD, CD, or MP3 player etc., based on a listener's position. The method includes sensing a listener's position and recognizing distance and angle information about the listener's position, determining output gain values and delay values of two speakers based on the distance and angle information about the sensed listener's position and selecting localization filter coefficients in a predetermined table, and updating filter coefficients of a localization filter based on the selected localization filter coefficients and adjusting output levels and time delays of the two speakers from the determined gain values and delay values.

Abstract: A first microphone device according to the present invention comprises a pair of directional microphones with high directivity in a sound collecting direction, a pair of nondirectional microphones with low directivity in the sound collecting direction, and a casing accommodating the pair of directional microphones and the pair of nondirectional microphones. The pair of nondirectional microphones is arranged so that sound collecting directions thereof are outward from both side surface walls of the casing, while the pair of directional microphones is arranged so that sound collecting directions thereof are outward from a front surface wall of the casing and intersect each other in vicinity of the front surface wall. All or a part of the pair of directional microphones is accommodated in a space sandwiched by the pair of nondirectional microphones.

Abstract: To provide an audio reproduction apparatus in which a general user inputs simple and easy settings so that audio beams of respective channels can be set. When an array speaker is installed in a room, the user inputs the shape of the room into the audio reproduction apparatus. Based on the shape of the room, the audio reproduction apparatus determines a beam control pattern indicating which directions audio signals of the channels should be formed respectively. The audio reproduction apparatus reads beam control data including delay times for forming the beams in the directions from a pattern memory, and automatically sets the beam control data in a DSP. Thus, only when the user inputs the shape of the room, the beams are controlled with a beam control pattern suitable to the room so that multi-channel audio can be reproduced optimally.

Abstract: An audio system for processing two channels of audio input to provide more than two output channels. The input may be conventional stereo material or compressed audio signal data. The audio processing includes separating the input signals into frequency bands and processing the frequency bands according to processes which may differ from band to band. The audio processing includes no processing of L?R signals.

Abstract: In processing a multi-channel audio signal having at least three original channels, a first downmix channel and a second downmix channel are provided, which are derived from the original channels. For a selected original channel of the original channels, channel side information are calculated such that a downmix channel or a combined downmix channel including the first and the second downmix channels, when weighted using the channel side information, results in an approximation of the selected original channel. The channel side information and the first and second downmix channels form output data to be transmitted to a decoder, which, in case of a low level decoder only decodes the first and second downmix channels or, in case of a high level decoder provides a full multi-channel audio signal based on the downmix channels and the channel side information.

Abstract: An acoustic processing device, includes an inputting section which receives a first audio signal and a second audio signal, a first input signal amplifying section which amplifies the first audio signal at an amplification factor, a second input signal amplifying section which amplifies the second audio signal at an amplification factor, a first initial delayed amplifying section, a first adding section which adds the first audio signal amplified by the first amplifying portion and the first audio signal amplified by the first input signal amplifying section, a second adding section which adds the first audio signal amplified by the second amplifying portion and the second audio signal amplified by the second input signal amplifying section, a first supplying section which supplies an audio signal output from the first adding section to a first sound emitting section, and a second supplying section which supplies an audio signal output from the second adding section to a second sound emitting section differen

Abstract: Provided is an adaptive remastering apparatus and method for a rear channel, which emphasizes only signals of the rear channel while maintaining signals of other channels of a multi-channel audio signal. According to the adaptive remastering apparatus and method for a rear channel, virtual rear left and right channel audio signals are generated by multiplying a predetermined gain by ambient signals extracted from front left and right channel audio signals and are combined with input rear left and right channel audio signals, thereby increasing powers of signals of the rear channel.

Abstract: A plural-channel audio signal (e.g., a stereo audio) is processed to modify a gain (e.g., a volume level or loudness) of an estimated dialogue signal (e.g., dialogue spoken by actors in a movie) relative to other signals (e.g., reflected or reverberated sound). In some aspects, a classifier is used to classify component signals in the plural-channel audio signal or the estimated dialogue signal. In some aspects, a desired volume level for the dialogue signal is maintained relative to the plural-channel audio signal or other component signals.

Abstract: A method for stereo expansion includes a step to remove the effects of actual relative speaker to listener positioning and head shadow and a step to introduce an artificial effect based on a desired virtual relative speaker to listener positioning using the inter-aural delay and the head-shadow models for the virtual speakers at desired angles relative to the listener thereby creating the impression of a widened and centered sound stage and an immersive listening experience. Known methods drown out vocals and add mid-range coloration thereby defeating equalization. The present method includes the integration of a novel binaural listening model and speaker-room equalization techniques to provide widening while not defeating equalization.

Abstract: A signal conditioner for subwoofers has a band pass filter which passes a lower frequency spectrum of an input signal. The band pass filter includes a high pass filter having a predetermined corner frequency, and a low pass filter having about the same corner frequency, and produces a filtered input to a peak voltage follower circuit. The peak voltage follower circuit traces and smoothes the upper boundary of the filtered input to produce a control voltage. An analog multiplier multiplies the input signal by the control voltage produced by the peak voltage follower to produce an enhanced signal where low frequency transients have been magnified.

Abstract: This invention is a method for binaural localization using a cascade of resonators and anti-resonators to implement an HRTF (head-related transfer function). The spectrum of the cascade reproduces the magnitude spectrum of a desired HRTF. The proposed method provides a considerably more computationally efficient implementation of HRTF filters with no detectable deterioration of output quality while saving memory when storing a large quantity of HRTFs due to the parameterization of its resonators and anti-resonators. Finally, the method offers additional flexibility since the resonators and anti-resonators can be manipulated individually during the design process, making it possible to interpolate smoothly between HRTFs, reduce spectral coloring or achieve higher accuracy at perceptually relevant frequency regions. These HRTF are useful in stereo enhancement and multi-channel virtual surround simulation.

Abstract: An audio output device includes: a speaker unit including at least first to third speakers; and an audio signal processor configured to select either one of a first mode for outputting a stereo audio signal from the first and second speakers and a second mode for outputting a monaural audio signal from the third speaker and the first or second speaker.

Abstract: A center channel positioning apparatus is provided, which does not cause strange feeling in sound quality even at a position apart from an original listener position. A sound signal processing unit (40) changes a phase of at least one of a left sound signal for center channel positioning (CL) and a right sound signal for center channel positioning (CR), based on a processing coefficient, and causes a left speaker (46) and a right speaker (52) to output sound based on a center channel sound signal (C). The processing coefficient is calculated based on the difference in level between both ears in the case where the left sound signal for center channel positioning (CL) for the left speaker (46), and the right sound signal for center channel positioning (CR) for the right speaker (52) are reproduced simultaneously.

Abstract: An apparatus and method for generating a binaural beat for brainwave induction is provided. Upon receipt of a stereo audio signal, a decorrelator extracts a common component existing in common in both channels of the stereo audio signal, and outputs the remaining stereo components except for the extracted common component. A frequency shifter generates a common component in which the binaural beat is included, by shifting a frequency of the extracted common component. First and second mixers mix the common component in which the binaural beat is included, with the remaining stereo components.

Abstract: With an array of speakers including a center speaker provided with left and right ultrasonic electro-acoustic transducers and left and right speakers provided with respective ultrasonic electro-acoustic transducers, it is possible to identify the left and right speakers. One approach includes energizing the left transducer of the center speaker to emit an acoustic ping signal, utilizing the transducers of the left and right speakers to detect the ping signal, measuring lapse of time between emission of the ping signal by said the left transducer and detection of the ping signal by the transducers of the left and right speakers. Then, the right transducer of the center speaker is energized to emit an acoustic ping signal, the transducers of the left and right speakers are utilized to detect the ping signal, and lapse of time between emission of the ping signal by the right transducer and detection of the ping signal by the transducers of the left and right speakers is measured.

Abstract: A speaker array is provided which can increase the orientation when reproducing front channels of a surround sound, increase the density effect, improve the narrow directivity when reproducing a stereo sound and increase the selectivity in selecting reproduction methods which match setting environments. When reproducing a stereo sound by a speaker array for reproducing a surround sound by converting a sound into a beam of sound, the speaker array is divided into a sound reproducing region for an L system and a sound reproducing region for an R system at a central portion thereof. Then, each of the reproducing regions so divided is further divided in to bands. In addition, since a high frequency reproducing region has a high directivity and a strong orientation when the sound is attempted to be reproduced simultaneously by the plurality of speakers as is described above, a reproducing region is limited to part of the reproducing regions.

Abstract: Aspects of the invention provide methods, computer-readable media, and apparatuses for digital processing of acoustic signals to create a reproduction of a natural or an artificial spatial sound environment. An aspect of the invention supports spatial audio processing such as extracting a center channel in up-mixing stereo sound for multi-channel loudspeaker setup or headphone virtualization. An aspect of the invention also supports directional listening in which sound sources in a desired direction may be amplified or attenuated. Direction and diffuseness parameters for regions of input channels are determined and an extracted channel is extracted from the input channels according to the direction and diffuseness parameters. A gain estimate is estimated for each signal component being fed into the extracted channel and an extracted channel may be synthesized from a base signal and the gain estimate. The input channels may be partitioned into a plurality of time-frequency regions.

Abstract: A circuit for processing multichannel audio signals, comprises a frequency characteristics correction device and an output device. The frequency characteristics correction device corrects frequency characteristics of an audio signal of a channel including an audio signal component having a predetermined frequency band, of audio signals of a multichannel comprising at least a right channel and a left channel, in accordance with correction characteristics determined based on a head related transfer function. The output device mixes the audio signal component having the frequency characteristics corrected with an audio signal of the right channel and an audio signal of the left channel to generate mixed output audio signals, and outputting the mixed output audio signals as a right channel output audio signal and a left channel output audio signal.

Abstract: An audio system including a left input channel signal, a right input channel signal, and a discrete center input channel. Circuitry removes correlated content from the left input channel signal and the right input channel signal and inserts the correlated content into the center input channel signal to provide a modified left input channel signal, a modified right input channel signal, and a modified center input channel signal. The modified left input channel signal is radiated by a directional loudspeaker so that radiation in a direction toward a listening area is less than radiation in other directions. The modified right channel input channel signal is radiated by a directional loudspeaker so that radiation in a direction toward a listening area is less than radiation in other directions.

Abstract: A sound reproducing apparatus is provided with a circuit comprising a first secondary phase shifter in a front stage of at least one of channels among a first power amplifier, a second power amplifier and a third power amplifier, and a second secondary phase shifter and an adder in at least one of remaining channels for providing an output by adding output signals of a music signal source and the second secondary phase shifter. The apparatus of this structure eliminates phase interferences between a center speaker and right and left speakers by controlling sound waves generated by the center speaker, thereby achieving excellent reproduction of music.

Abstract: An audio signal is supplied to a loudspeaker array to perform wavefront synthesis. A virtual sound source is produced at an infinite distance using wavefront synthesis. A propagation direction of a sound wave emitted from the virtual sound source is changeable.

Abstract: A method includes splitting and filtering a left input signal and a right input signal to produce a plurality of frequency sub-bands. Each of the frequency sub-bands includes a left sub-band signal and a right sub-band signal. The method also includes processing the left and right sub-band signals associated with each of the frequency sub-bands into a plurality of sub-band channel signals. The plurality of sub-band channel signals includes at least three sub-band channel signals. In addition, the method includes summing corresponding ones of the sub-band channel signals for reproduction in a corresponding channel of a plurality of channels. The plurality of sub-band channel signals may include a left sub-band channel signal, a right sub-band channel signal, a center sub-band channel signal, a left surround sub-band channel signal, and a right surround sub-band channel signal.

Abstract: A digital signal processing system and method transforms pairs of channels selected from a multichannel signal into the frequency domain. Vector operations are performed upon the frequency-domain data by which signal components unique to one of the input channels are routed to one of the output channels, signal components unique to the other of the input channels are routed to another of the output channels, and signal components common to both channels are routed to a third and optionally to a fourth output channel. The frequency-domain output channels are then transformed back into the time-domain, forming a plurality of time-domain output channels. The vector operations are performed in a manner that preserves the overall information content of the input data.

Abstract: A variable equalizer apparatus for forward and/or reverse equalizers in an amplifier. The system can include a structure to allow continuous contact of the signal flow as an equalizer is removed; jumpers with fixed resistors and associated capacitors and inductors to produce a variable range over many different values; and/or variable resistance potentiometers with fixed resistors and associated capacitors and inductors to produce a variable range over separate value equalizers.

Abstract: An audio upmixer, such as a two-channel to three-channel upmixer, employs a difference in a measure of sound at the ears of a listener in accordance with first and second models, one based on a reproduction of the original channels and the other based on a reproduction of the upmixed channels. The difference is minimized while simultaneously causing a, portion of one or more of the stereophonic channels to be applied to the center loudspeaker under some conditions of the signals in the stereophonic channels, the portion being commensurate with the value of a weighting factor, such that the weighting factor controls a balance between two opposing conditions, one in which no signals are applied to the center loudspeaker and another in which no signals are applied to the left and right loudspeakers.

Abstract: The disclosed subject matter relates to an architecture that can facilitate generation of enhanced spatial effects for stereo audio systems. Such can be accomplished by integrating on top ambience signal boosting employed in conventional systems. In particular, the ambience signal can be transformed according to a time-dependent function, which can simulate the auditory impressions of a real-world listening environment that may contain static, regularly moving, and/or irregular moving elements.

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: There are provided methods and an apparatus for processing audio signals. According to one aspect of the present invention there is included a method for processing audio signals having the steps of receiving at least one audio signal having at least a center channel signal, a right side channel signal, and a left side channel signal; processing the right and left side channel signals with a first virtualizer processor, thereby creating a right virtualized channel signal and a left virtualized channel signal; processing the center channel signal with a spatial extensor to produce distinct right and left outputs, thereby expanding the center channel with a pseudo-stereo effect; and summing the right and left outputs with the right and left virtualized channel signals to produce at least one modified side channel output.

Abstract: An audio processing apparatus comprising: channel determination section for determining which one of a combination of the first left audio signal and the first right audio signal and a combination of the second left audio signal and the second right audio signal is included in multichannel audio data; and switching section for causing the first amplification section to amplify the first left audio signal and supply the amplified first left audio signal to the first speaker terminal and causing the second amplification section to amplify the first right audio signal and supply the amplified first right audio signal to the second speaker terminal when the combination of the first left audio signal and the first right audio signal is determined to be included; and causing the first amplification section to amplify the second left audio signal and supply the amplified second left audio signal to the third speaker terminal and causing the second amplification section to amplify the second right audio signal and su

Abstract: Modifying a panned source in an audio signal comprising a plurality of channel signals is disclosed. Portions associated with the panned source are identified in at least selected ones of the channel signals. The identified portions are modified based at least in part on a user input.

Abstract: A wide mono sound reproducing method and apparatus to widen mono sound by using 2 channel speakers. The method include separating an input mono sound signal into a plurality of decorrelated signals, generating virtual sound sources by localizing each of the separated signals at virtual locations asymmetrical about a center of a front side of a listening point by applying different head related transfer functions to the separated signals, and canceling crosstalk of the generated virtual sound sources.

Abstract: An array loudspeaker is constructed by stacking loudspeaker rows in a plurality of stages, each of the loudspeaker rows being formed by arranging loudspeaker elements in the form of a horizontal line. The loudspeaker rows are arranged in a zigzag form by, for example, offsetting the positions of the loudspeakers in the left and right direction for each stage. As for a high range signal, a two-stage portion of halves of the loudspeaker rows is used to narrow the pitch of the loudspeaker elements so as to prevent the grating lobe. As for a low range signal, the entire single-stage loudspeaker row is used to alleviate the deviation with respect to the directivity characteristics of the high range.

Abstract: A motion picture soundtrack reproduction system has a center front soundtrack channel and a plurality of other soundtrack channels. A volume control adjusts the gain of all the channels. The volume control has a range of settings from a minimum to a maximum, the gain of the center front channel having substantially a first relationship to the volume control settings and the gain of the other channels having substantially a second relationship to the volume control settings, the relationships being such that for a range of volume control settings less than a first setting the gain of the center front channel remains substantially constant while the gain of the other channels decreases as the setting decreases or decreases more gradually than the gain of the other channels as the setting decreases.

Abstract: A motion picture soundtrack reproduction system has a center front soundtrack channel and a plurality of other soundtrack channels. A volume control adjusts the gain of all the channels. The volume control has a range of settings from a minimum to a maximum, the gain of the center front channel having substantially a first relationship to the volume control settings and the gain of the other channels having substantially a second relationship to the volume control settings, the relationships being such that for a range of volume control settings less than a first setting the gain of the center front channel remains substantially constant while the gain of the other channels decreases as the setting decreases or decreases more gradually than the gain of the other channels as the setting decreases.