Masaharu Matsumoto

Sound field controller

According the present invention, a sound field controller for reproducing a sound field with presence comprising; input terminals for inputting an audio signal having a first and a second channel signals, a signal extracting circuit for receiving and processing the audio signal, and producing an extracted signal of the audio signal, an operation circuit for receiving the extracted signal from the signal extracting circuit, performing the convolution on the extracted signal, and generating a convolution sum signal, a delay circuit for delaying the convolution sum signal by a predetermined time, and producing a delayed signal, an adding circuit for receiving the audio signal and the delayed signal, and adding the audio signal and the delayed signal with a predetermined summation ratio to produce a summed signal, and output terminals for reproducing the summed signal to localize a sound image in a desirable direction.

Sound image localization device and sound image localization method

A sound image localization apparatus comprises a signal source for outputting an audio signal; a localization angle input unit for receiving an angle of a sound image to be localized; a coefficient control unit for receiving sound image localization angle information from the localization angle input unit, reading coefficients from a coefficient memory in accordance with the information, and outputting the coefficients; first, second, and third multipliers for multiplying the audio signal output from the signal source by using first, second, and third coefficients output from the coefficient control means, respectively; a first signal processing unit for receiving the output from the second multiplier, and processing it by using a filter having a predetermined first frequency response; a second signal processing unit for receiving the output from the second multiplier, and processing it by using a filter having a predetermined second frequency response; a first adder for adding the output from the first multiplier and the output from the first signal processing unit to output the sum; a second adder for adding the output from the third multiplier and the output from the second signal processing unit to output the sum; a first output unit for outputting the output of the first adder; and a second output unit for outputting the output of the second adder.

Audio processing on AV decoder LSI for DVD-audio

We have developed an AV (audio and video) decoder LSI for both DVD-audio and DVD-video standard. We describe the architecture of the LSI and the audio software algorithms for real-time decoding of high quality audio contents (192 Hz 24 bit stereo, 96 kHz 24 bit multi-channel, etc.) with still picture.

The multi-channel sound field control system in a multi-purpose hall

Abstract In this study, the effect of a digital sound field control system (DSFC) with loudspeakers arranged three-dimensionally in a multi-purpose hall is discussed. A method is presented of making the tap data set up in the DSFC, based on simulated reflection patterns using the usual ray tracing method. Each reflection is ultimately divided into two vectors which make phantom images when they are reproduced by two loudspeakers, while the three-dimensional information of reflection pattern is comparatively preserved. The advantage of this method is that reflections can be produced using small sized hardware. One application of DSFC based on this method is shown in an existing shoebox-type multi-purpose hall, where one side of the wall is flat and hard, while another wall facing it is covered with diffusers, and the reflection patterns of this hall are very unique. The target reflection patterns can be obtained in this specific hall by using the DSFC.