active crossover filter - for active loudspeaker systems

active crossover filter elektor september 1984 active crossover filter for active loudspeaker systems In electronics we call a circuit "active" if, along with the usual (passive) components like resistors, capacitors and inductors, it contains an amplifying element. It is ob- vious, therefore, what an active filter is, but the term "active loudspeaker" may not seem so obvious. A loudspeaker, which really only consists of the cabinet and drive units (the actual loudspeakers), can, strictly speaking, only be passive, unless it has some mechanical feedback. In general, however, a loudspeaker equipped with an active crossover filter is called an active loudspeaker. This is partly due to the fact that power amplifiers are then often built into the loudspeaker cabinets. The differences between active and passive loudspeaker systems can be seen with the aid of the diagrams in figure la and figure lb. In the passive system (figure la) the output signal from the preamplifier is passed thro...