80Hz and 8KHz
These filters have a shelve curve. Bass and treble adjustments are controlled by the [80Hz] and [8kHz] knobs with a range of +/- 15dB.
Semi-parametric (sweep frequency) equalizer with a broad fixed bandwidth. The upper knob progressively adjusts the central frequency from 200Hz to 8kHz, the lower knob adjusts the gain of the filter.