Click on a letter or number to jump to listings of terms that correspond. [ 5 | A | B | C | D | E | F | G | H | I | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y ] Term Definition Demo AC see Alternating Current AC Line Conditioner or Protector A device inserted between the wall outlet and your equipment to isolate it from voltage spikes and unwanted high frequency signals that may be picked up by the power lines. High quality audio equipment may already have some of this kind of isolation built in. See also: AC Voltage Stabilizer AC Voltage Stabilizer A device inserted between the wall outlet and your equipment to maintain a constant voltage level. Used in buildings and neighborhoods where line voltage fluctuates widely because of heavy variable loads. AC-3 The first descriptor for what is now called Dolby Digital. Acoustic Suspension A closed box loudspeaker enclosure in which the compliance (spring) of the air inside the box is a substantial portion of the total compliance of the system, including the mechanical suspension of the woofer. See: Suspension, Compliance Acoustical Interference When two or more sounds arriving from different directions combine at a point in space, e.g. at an ear or microphone, those components which are in step with each other (in phase) will add (constructive interference) and those that are out-of-phase will subtract, or cancel each other (destructive interference). See: In Phase, Out-of-Phase, Comb Filter. Acoustics The physical science dealing with how sound is produced, propagated, manipulated and perceived. See also: Room Acoustics Active Crossover An analog or digital device performing high-pass, low-pass and bandpass functions ahead of power amplifiers driving the transducers in a loudspeaker. Active Loudspeaker A loudspeaker which has a built-in power amplifier for at least one driver, usually the woofer or subwoofer. It may also have amplifiers for mid and high frequency drivers. See: Powered Tower Active Matrix Decoder See: Matrix Encode/Decode