Introduction
In sound systems it is often desirable to have a flat frequency response along the range of human hearing (20Hz - 20kHz). While this goal can be easily achieved for a single loudspeaker system, it is challenging to achieve a perfectly flat response in the multi-speaker systems. In the large venues where multi-speaker sound reinforcement systems are necessary it is possible for the frequency response in one location be vastly different from the response in another. Summation effects from the multiple sources cause this spatial variance in the frequency response. If two audio sources are at a similar level and significantly out of phase (150 - 210 degrees)they can cancel resulting in audible "dead zones".
