Psycho-acoustic signal processing is often utilized to produce special effects in a multi-channel audio system. For example, by proper mixing of audio signals in a two channel stereo audio system, sounds can appear to emanate from locations other than the two loudspeakers (speakers). For example, a sound can be mixed between the two loudspeakers so that it appears to emanate from between the two loudspeakers. This effect is often used to simulate the sound of a passing automobile that appears to move from left to right or vice versa. With larger numbers of loudspeakers, more dramatic audio effects are commonly produced.