Filter Circuit
Filter circuit describes how an equalizer or crossover implements its frequency-selective filters: active analog, passive analog or digital processing.
Passive networks use resistors, capacitors and sometimes inductors; active analog filters incorporate powered circuitry. DSP performs the filtering digitally. The filter network and the surrounding gain stages should be distinguished.
Filter Circuit — Equalizer
An active analog equalizer shapes the signal using filters built around powered gain stages. Passive LC filters use inductors and capacitors; passive RC filters use resistors and capacitors without inductors. A passive filter network may be followed by an amplifier that restores the signal level lost in filtering.
Compare the filter circuit separately from whether the unit uses tubes or transistors. A powered enclosure does not by itself establish active filtering, and a digital display does not establish DSP. The circuit category alone predicts neither tonal character nor accuracy; available curves, headroom, noise and distortion require their own information.
Crossover Circuit — Crossover
An analog active crossover filters the signal at line level using powered stages. An unpowered RC network can also divide line-level signals, while passive LC networks use coils and capacitors. A DSP crossover processes digital data, including when it first converts an incoming analog signal to digital.
Compare the intended signal level, source and load requirements, and available crossover settings. Analog sockets do not prove an all-analog path. Passive networks can depend on the impedance of the connected equipment, so their stated operating conditions matter. This circuit label does not specify the number of ways, filter slope or digital processing delay.