Ashly PQX 571 Pro Audio Parametric EQ / Equalizer

In outstanding condition. World-class pro audio EQ for a bargain price. Works great! The Ashly PQX Series equalizers are a third generation design including many refinements on the original PQ models. Lower noise, greater headroom, additional filters, full 20Hz -20KHz range on all parametric filters, and additional connector types are the result. The heart of the PQX equalizers is a unique bandpass filter circuit. Basically a "state-variable" type, this filter is trimmed and optimized to provide excellent transient response and a wide range of frequency and bandwidth adjustment. Each filter can be tuned over a 100:1 frequency range (about 6.6 octaves) and a 70:1 bandwidth range with no more than a 2 dB amplitude error at center frequency. At its sharpest setting, the filter has a "Q" of about 35 and generates a response curve with 3 dB points only 1/20 octave apart, making feedback control possible with no audible side effects. Each filter is placed in the feedback loop of a summing amplifier to produce the desired frequency response. Since a separate summing amplifier is used for each band, no interaction between bands occurs. After twenty years of refinement, the Ashly parametrics are the most powerful equalization tool available. They especially excel in control of resonance and feedback yet also provide smoother broadband tone shaping than Graphic equalizers.