Term	Definition	Demo
Power	The amount of energy delivered or used by a device or system, expressed in Watts. In audio, power ratings of amplifiers and loudspeakers are subject to a lot of variation and uncertainty because of the very large difference in the long-term, steady-state, power rating, and the transient, or momentary, power rating, which can be several times larger. Further confusion is added when ratings at a single frequency (say, 1 kHz) are compared with the more realistic 20 - 20 kHz rating. In multichannel amplifiers, there is the further variable of ratings done with a single channel operating vs. ratings with all channels operating. The result, for consumers, is that advertised power ratings are often almost meaningless.
Power Compression	In loudspeakers at high sound levels, an effect in which the acoustical output of the device increases less than the electrical input to the device. Caused mainly by the heating of the voice coil, and the consequent increase in electrical resistance. In multi-way systems, power compression affects the different drivers differently, causing the loudspeaker system to have a different spectral balance at different sound levels.
Power Handling	The amount of power that may be applied to a device without causing destruction. May be expressed as "RMS" or as "continuous average" to indicate how much power can be applied for long periods. It mnay also be expressed as "peak" to indicate how much power can be applied for extremely short periods--the beat of a drum, for instance. See also Power
Power Rating	See: Power.
Powered Tower	A floor-standing loudspeaker with an amplified woofer or subwoofer.