Sound amplification by stimulated emission of radiation of the laser. In a SASER device, a source (e.g., an electric field as a pump) produces sound waves (lattice vibrations, phonons) that travel through an active medium. In this active medium, a stimulated emission of phonons leads to amplification of the sound waves, resulting in a sound beam coming out of the device. The sound wave beams emitted from such devices are highly coherent. The first successful SASERs were developed in 2009. Instead of a feedback-built wave of electromagnetic radiation (i.e., a laser beam), a SASER delivers a sound wave. SASER may also be referred to as "phonon laser",
A/B Sound System 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