Yamaha Corporation

Hiraku Okumura

Mikio Tohyama

Yoshikazu Honji

Koji Niimi

Toru Hirai

Hiroshi Iriyama

Hiroaki Fujita

Futoshi Shirakihara

Tadashi Morikawa

Katsumi Ishikawa

Kentaro Noto

Hirobumi Tanaka

Yoshinori Takahashi

Satoshi Sekine

An audio signal processing method obtains a plurality of audio signals, determines a type of each audio signal of the plurality of audio signals, sets positions of a plurality of virtual speakers, generates, in a case where an audio signal among the plurality of audio signals is determined to be a first type, a first audio signal by performing localization processing on the audio signal determined to be the first type to localize an acoustic image of the first audio signal at a position of any one virtual speaker of the plurality of virtual speakers, generates, in a case where an audio signal among the plurality of audio signals is determined to be a second type, a second audio signal by performing distributed processing on the audio signal determined to be the second type to distribute and localize an acoustic image of the second audio signal at positions of two or more virtual speakers of the plurality of virtual speakers, generates an addition signal by adding the first audio signal and the second audio signal, and outputs the addition signal to a plurality of real speakers.

Audio signal processing method and audio signal processing apparatus

A live data distribution method obtains first sound source information according to sound of a first sound source generated at a first location of the first venue and position information of the first sound source, and second sound source information according to a second sound source including an ambient sound generated at a second location of the first venue, as distribution data, distributes the distributed data to the second venue, and renders the distribution data and providing first sound of the first sound source having been performed with localization processing based on the position information of the first sound source, and second sound of the second sound source, at the second venue.

Live data distribution method, live data distribution system, and live data distribution apparatus

A live data distribution method obtains information on a sound source according to sound generated at the first venue, and information on space reverberation, as distribution data, distributes the distribution data to the second venue, and renders the distribution data and providing sound according to the distribution data at the second venue.

A talk deciding system includes a receiving portion which receives far-end side decision information indicating a talking state on a far-end side, an inputting portion which inputs an emitted signal from the far-end side, a speaker which emits the emitted signal being input into the inputting portion, a microphone which picks up a voice on a near-end side and outputs a picked-up signal, and a deciding portion which preliminarily decides a talking state on the near-end side based on the picked-up signal being output from the microphone and the emitted signal being input into the speaker, and generates near-end side decision information indicating a talking state on the near-end side. The deciding portion decides the talking state on the near-end side based on the far-end side decision information being received at the receiving portion and the near-end side decision information.

Talk deciding system

A howling suppression apparatus suppresses a howling caused in an acoustic system including a sound collection device and a sound emission device. An estimation part generates an estimated signal by estimating a feedback sound reaching the sound collection device from the sound emission device. An adjustment part generates an estimated signal by adjusting the estimated signal. A spectrum subtraction part generates an acoustic signal using a result of subtracting a frequency spectrum of the estimated signal from a frequency spectrum of an acoustic signal. A filter part generates an acoustic signal by suppressing a component of a frequency band including a howling frequency F among the acoustic signal. An acoustic signal in which the acoustic signal is amplified by an amplifier is supplied to the sound emission device.

Howling suppression apparatus and computer readable recording medium

In an audio processing apparatus, a signal processor controls a volume of a sound signal provided to a sound emitting device. An adaptive filter determines an adaptive signal so as to minimize a magnitude of an error signal. A subtractor generates the error signal represented by a difference between the adaptive signal and an observation signal generated by a sound receiving device. A magnitude ratio calculator calculates a magnitude ratio of the observation signal relative to the error signal or a magnitude ratio of the adaptive signal relative to the error signal for each frame that is sequentially segmented from the error signal along a time axis. A controller variably controls a gain of the volume of the sound signal according to the magnitude of the error signal and the magnitude ratio.

Audio processing apparatus and program

An anti-feedback device includes an anti-feedback filter provided in a closed loop. The anti-feedback device down-samples a signal of specific band selected from an output signal of an adaptive target signal transfer system and a signal of the same band selected from an input signal of the transfer system, and a filtering coefficient of the adaptive filter is updated by use of the down-sampled signals. The filter controller controls a filtering characteristic of the anti-feedback filter so that a peak gain of a frequency of an amplitude characteristic within a specific band of a closed loop determined from the filtering coefficient of the adaptive filter is suppressed. Moreover, the filter controller estimates a gain of the closed loop outside the specific band from the amplitude characteristic in the specific band and controls the amount of suppression of the anti-feedback filter outside the band in accordance with a result of estimation.

Anti-feedback device and anti-feedback method

Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (-to-) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.

Multi-channel echo cancel method, multi-channel sound transfer method, stereo echo canceller, stereo sound transfer apparatus and transfer function calculation apparatus

An adaptive howling canceller has a plurality of adaptive filters. A delay adds a time delay of an acoustic feedback path to an electric signal fed from an amplifier of a sound-reinforcement system. Each adaptive filter filters the output signal of the delay with a filter coefficient, which is periodically updated at an update interval. The update interval of each adaptive filter is set to decrease successively from a first one to a last one of the adaptive filters. Adders are arranged in correspondence to the adaptive filters in series between a microphone and the amplifier. Each adder subtracts the output signal of the corresponding adaptive filter from an output signal fed from a preceding adder to thereby provide an output signal to a succeeding adder. The output signal from each adder is inputted into the corresponding adaptive filter. The audio signal from the microphone is inputted to the first adder, while the output signal from the last adder is inputted through the amplifier to the speaker and to the delay as the electric signal. The filter coefficient of each adaptive filter is updated so as to simulate a transfer function of the acoustic feedback path based on the output signals of the corresponding adder and the delay.

Adaptive howling canceller

In an audio amplification apparatus connected to a microphone and a speaker, an audio amplification circuit amplifies an audio signal and inputs the amplified audio signal to the speaker. A howling canceller has an adaptive filter which is set with a filter coefficient based on the audio signal input to the speaker and a residual signal so as to simulate a feedback transmission path from the speaker to the microphone such that the adaptive filter processes the audio signal to produce a simulation signal. The residual signal is obtained by subtracting the simulation signal from an input audio signal inputted from the microphone and fed to the audio amplification circuit. An internal sound source generates the audio signal and inputs the audio signal to the speaker. A sound source determination portion determines whether or not the input audio signal contains an external audio signal provided from an external sound source other than the audio signal fed back from the speaker to the microphone, and controls update of the filter coefficient in accordance with a result of the determination.

Audio amplification apparatus with howling canceler

A method is designed for emphasizing a howling frequency component of a sound signal observed in an acoustic feedback system during an observation period having a predetermined length. The method is carried out by the steps of successively sampling the sound signal from the acoustic feedback system to provide a running set of samples of the sound signal during the observation period such that a total number of the samples in the running set increments each time one or more of new sample is added to the running set until the total number of the samples corresponds to the predetermined length of the observation period, recurrently calculating a running frequency characteristic of the sound signal on a common frequency axis for the observation period from the running set of the samples each time one ore more of new sample is added to the running set, and accumulating the recurrently calculated running frequency characteristics on the common frequency axis so as to emphasize a howling frequency component contained in the sound signal.

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Hamamatsu, Japan

Hiraku Okumura