Motivation
This is my adaption of the Elektor Formant RFM module as described in Elektor Formant book 2 pg28ff. I put only one filter in this module, so you can build as many as you want or need. It is a state variable filter with variable volume, Q (resonance) and frequency. It is thought to emphasize a certain frequency range. This can be used to reproduce the resonances of acoustic instruments. With the given values the frequency range is 50..2300Hz, Q 0.8..5, vol. 0..1.
Specs and features
- Band pass with variable center frequency and Q
- Runs on +/-12V and +/-15V
- Power consumption below 20mA each rail
Implementation
Schematic
Parametric Equalizer, Resonating Filter schematic: Control board
Description:
This is basically a SVF. Please refer to the original article(Elektor Formant book2 pg 28ff) and other implementations on the web.
Calibration
- None
Building hints
- You can adapt the frequency range to your needs. The description can be found in the original article.
Special parts
- None
Download
Parametric Equalizer, Resonating Filter control board documentation downloadParametric Equalizer, Resonating Filter control board Gerber files download
Parametric Equalizer, Resonating Filter *.fpd file download
Parametric Equalizer, Resonating Filter: Front view
Parametric Equalizer, Resonating Filter: Populated control PCB
Parametric Equalizer, Resonating Filter: Back view
Parametric Equalizer, Resonating Filter: Half front view
