Qsound Ltd.

John W Lees

Danny D Lowe

The illusion of distinct sound sources distributed throughout the three-dimensional space containing the listener is possible using only conventional stereo playback equipment by processing monaural sound signals prior to playback on two spaced-apart transducers. A plurality of such processed signals corresponding to different sound source positions may be mixed using conventional techniques without disturbing the positions of the individual images. Although two loudspeakers are required the sound produced is not conventional stereo, however, each channel of a left/right stereo signal can be separately processed according to the invention and then combined for playback. The sound processing involves dividing each monaural or single channel signal into two signals and then adjusting the differential phase and amplitude of the two channel signals on a frequency dependent basis in accordance with an empirically derived transfer function that has a specific phase and amplitude adjustment for each predetermined frequency interval over the audio spectrum. Each transfer function is empirically derived to relate to a different sound source location and by providing a number of different transfer functions and selecting them accordingly the sound source can be made to appear to move.

Sound imaging method and apparatus

Sound location information provided in the game program of a video game is employed by a sound processor to produce two-channel sound signals that provide an apparent location of a sound source to the video game player that need not correspond to the actual locations of the loudspeakers. The sound processor processes the sound signals produced by an audio synthesizer of the kind known for use in a video game system in accordance with audio information contained in the game program cartridge. The sound processor can be connected to the central processing bus along with the audio synthesizer. Alternatively, the sound processor can be connected to a separate audio synthesizer, both of which are connected to the video game system through a parallel bus provided therein for communication with the central processing unit bus. In another approach, the sound processor and synthesizer are connected to the video game system through a serial or parallel port provided therein for communication with the central processing unit.

Sound imaging apparatus connected to a video game

The game software for a video game system includes audio data and sound positioning information, in order that the audio data can be processed in accordance with the sound positioning information and played back over two spaced-apart speakers to give the player the impression that the sound is emanating from a location other than the actual speaker locations. A sound processor operates upon monaural signals from an audio synthesizer in response to the sound positioning information from the game software so that each monaural signal from the audio synthesizer is divided into two signals and at least one of the signals is passed through a transfer function to produce two-channel output signals that have a differential phase and amplitude relationship therebetween that is adjusted on a frequency dependent basis. Each different sound location generally requires a specific different relationship, and the sound processor for the video game may include a number of different transfer functions, each of which can be embodied by adjusting a digital filter in response to the sound positioning information. Each digital filter alters the amplitude and phase of the applied signal in a frequency dependent manner over the audio frequency spectrum.

Sound processor for video game

A game software for a video game system includes sound positioning information that utilizes two spaced-apart speakers to give the player the impression that the sound is emanating from a location other than the actual speaker locations, for example, to the far right or the far left of the speakers. A sound processor operates in conjunction with a sound synthesizer similar to the one normally employed in a video game system to process the synthesized sound signals in accordance with the sound location information from the software so that it can be reproduced over the two speakers. By arranging the sound processor at various locations relative to the existing sub-systems of the video game, all existing and future video game systems can be adapted to utilize sound location information contained in the game software. In addition, synthesized sound signals from video game software that does not include sound positioning information can be enhanced.

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Calgary, Canada

John W Lees