A/B sound system

An A/B sound system is a type of sound reinforcement system or public address system. Unlike a more typical sound reinforcement system, an A/B sound system provides two electrically isolated signal paths from microphone to speaker, resulting in a system where signals from two microphones only interact acoustically and never interact electronically. This is accomplished by placing two separate loudspeakers at each speaker position and feeding the two speakers separate signals from separate microphones. The purported benefit of such a system is a reduction in phase cancellation and intermodulation distortion, and an improvement in speech intelligibility when two microphones are used simultaneously. A/B sound systems are unusual because they require double the speakers and therefore have double the cost.