16 band Graphic Equalizer


16 Band Graphic Equalizer

This is a Biquad filter based graphic equalizer with 16 half-octave frequency bands. It features a control and meter for each band and a final gain control


Input Signal Range Notes
input -1 to 1 audio

Output Signal Range Notes
output -1 to 1 audio


[Knob, Button, Spline, and/or Mapper] Function Notes
knob level adjust for band 50% is unity gain


Meter Displays Notes
meter level for each band 50% is unity gain
gain output gain dB scale

Version History

Revision File Date Notes
1.2 equalizer V1.2.audulus (181.1 KB) 05/27/2018 reduce max gain to 24dB - minor bug fixes
1.1 superceded 05/14/2018 initial upload to new forum




I like it !
I dream of the same kind of module but with a resonance on each frequency like the Serge Resonant Equalizer and a feedback control.

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The bi-quad filters I used in this unit have resonance so it would be pretty easy to mod it for resonance for each band


I have no knowledge to make this change, do you think that one day you will be able to do it? I thank you in advance.


I’m working on modeling the Serge Equalizer. I’ve modified the frequency bands to match the original but I’m at a bit of a loss regarding the “resonant” aspect. Generally when a filter is referred to as resonant, it exhibits a response peak around the center or cutoff frequency. In this case, the filters are peaking eq type filters so they all exhibit a response peak when the gain at the center frequency is > 1. In that sense all equalizers are already resonant. In the description of the unit it states that:

“When the knobs are positioned between the 9 and 3 o’clock position, up to 12 db of boost or cut is set at the band. If the knob is set beyond the 3 o’clock position, the band will become resonant, simulating the natural resonance of acoustic instrument formant structures. Below the 9 o’clock position, increased band rejection is achieved.”

After thinking about this I’m not really sure what it means. Does the boost or cut simply become more intense? With a peaking eq style filter the Q (which is typically a measure of resonance) and the bandwidth are inversely proportional. Are they implying that the bandwidth of the frequency band narrows as you increase the control past the 3 - 9 o’clock position? Does anyone have any experience with this type of filter? I haven’t been able to find a more detailed description so at this point I’m just guessing. I’m thinking that the bandwidth must become narrower which would create a more defined peak.


I’ve posted a ten band “resonant” equalizer here:Ten Band Resonant Equalizer

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