ABSTRACT
Surround sound is a 'catch-all' term often used to describe any form of loudspeaker sound reproduction that involves more than two loudspeakers and attempts to surround the listener with sounds from multiple directions. It started as a marketing term that aimed to imply something more spatially interesting than 2-channel stereo. In this chapter, therefore, the discussion will be restricted to approaches based on conventional stereophonic principles that range from three channels upward, but don't involve height information. Three front channels were the norm in cinema sound reproduction for many years, partly because of the wide range of seating positions and size of the image. The chapter also discusses the evolution of surround sound. Spatialization of sound images in basic stereophony was achieved by the introduction of simple time and/or level differences between channels, created out of the relationships between microphone outputs or by simple panpots. The aim was one of creating an adequate spatial illusion.
