The Number of Audio Channels
Although today 2-channel stereophonic sound still predominates home listening, 5.1-channel stereo is the emerging and rapidly growing format due to its adoption by video and advanced television for the next generation. Now that restriction to the number of audio channels may be alleviated because of higher capacity media, the optimum number of audio channels should be re-examined. The 5.1-channel system was made for sound accompanying a picture but was not intended to produce sound images from all directions around the listener, and the choices made for it were limited to the available space on the media.: Two prominent fields were studied briefly to extend the understanding of multichannel sound: room acoustics and psychoacoustics. While it is axiomatic that the job of reproduction is to transport the listening from one space to another, many factors known in concert hall design that have emerged over the last 15 years as sonically important have not been generally reflected in the design of reproduction systems. Furthermore, the psychoacoustic literature tells us about spatial capabilities of hearing, but the results have only been reflected in the most direct ways in the design of sound systems, such as the horizontal place orientation of the 2- and 5.1-channel systems.: While more channels will always be better than fewer ones (Gerzon suggested one million), there is a law of diminishing returns, and inevitably the number of channels will be traded off against the other two defining issues for any digital media: sample rate and coding. The purpose of this work is to provide a foundation for discussion on the number of audio channels.
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