Pole mixing filter

I’ve posted some things about pole mixing filters. Here, finally, is a post about an actual pole mixing filter. I don’t have the final front panel yet, but this module seems to be working: It’s a multimode VCF based on a (partial) design by Electric Druid. I made a number of modifications but the basic design is […]

Pole mixing cancellation redux

Amazing what a good walk will do for your thought processes. I’d hardly set foot on the trail when I realized the pole mixing problem isn’t as serious a problem as I thought. The thing about the gains depending on the control voltage is they’re correlated. All four gains change about the same amount in […]

Pole mixing on the breadboard

Electric Druid shows a pair of partial designs for a pole mixing filter, one based on the V2164/AS2164 filter chip and one using the AS3320. I’ve been breadboarding a circuit based on the latter, and my results have… not been encouraging. There are a couple of errors in the Electric Druid schematics. There should be […]

Pole mixing

A while ago I mentioned pole mixing in a post about my all pass filter module. Pole mixing is a technique of combing the outputs of different poles in a filter with the input signal to get different kinds of frequency responses. For instance, suppose you have a simple 1-stage (or 1-pole) low pass filter. […]