The FE4 Three Band EQ prototype is up and running, and I'm honing in on the tuning. This is a parametric equalizer with shelving type bass and treble controls and a peaking midrange control. In addition to boost and cut, all three bands have a sweepable frequency control using a stacked pot with frequency on the bottom and a detented boost/cut on the top. The bass and treble filters are a high-performance design with cleanly separated frequency and boost controls, and the midrange is a bit higher Q than usual for a punchy and sensitive midrange control.
The frequency ranges are tuned around a 500 Hz center, with the bass and treble coming up around 4 dB at the center, and the midrange adjustable from 220-1200 Hz. See the frequency response chart to get an idea of the tuning as it is right now. The bass control is low enough to serve as a high pass filter for eliminating "boominess" when cut at the lowest frequency, and the treble can go from a barely audible tinkle at the extreme high end to a single-coil-ish 2-4k boost. It is very quiet, and the whole thing draws only 2.2 mA.
I'm really digging it so far. It's going to be a tasty alternative to the dual filter options that Underhill has been focused on.
This is such a great idea. Now I just need to get yet another bass to put one of these in there.
I love the concept