Surround Quality Objectives

Surround sound signals may include ambient and discrete sounds. Holman writes: “surround sound is used best aesthetically where is does not contain many discrete sounds that draw attention to themselves, for there is no supporting picture as there is with the screen channels and one’s attention is drawn to the loudspeaker”[5]. This statement is interesting since it implies a criterion for performance for surround reproduction that is more related to listener envelopment than precise localisation of discrete images all around the listener. In fact the localisation of a surround speaker itself is regarded by Holman as a failure to maintain the desired illuson. The front sound has a totally different criterion, precise imaging being a key performance attribute.

Although the technical achievement of delivering localised images around the listener is unquestionable we should not forget that the purpose of surround sound is to enhance the illusion provided by cinematic material. It is the opinion of the authors that this is best achieved by enveloping the listener in a diffuse field.

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