Does anyone know of analog synths employing a bandpass/bandstop/highpass filter design which is not state-variable? (it seems rather few analog synths have a multimode filter to begin with)

Richard

moog multimode ladder, i *think* it's not SVF

Used where? I don't know of any Moog synth with a multimode filter.

Richard

Not entierly sure what a SVF really is but how about the Oberheim Matrix 12/XPander ? Don't think they're SVF.

The Korg35 as used in the MS10 and MS20 are Sallen-Key types and not SV filters.

Google:

A Study of the Korg
MS10 & MS20 Filters
Timothy E. Stinchcombe

Regards
Andrew

True, thanks- never looked at the Korg filters in detail.

Btw the reason I ask is that it doesn't seem to be straightforward to transform a nonlinear filter design (e.g. the Moog ladder) to bandpass, notch or highpass.

Richard

Have you looked at what I call "mystran's Biquad to SV Filter"? (he didn't give it a name,yet). It's mentioned on some filter related thread here at KVR. Could do any response that a biquad can - same formulas + conversion. But with better stability and is also delayless I think.

Andrew

Korg MS filters and Xpander modes (summing outputs from the individual stages of a 4-pole/3-pole cascade) come to mind first. The latter is explained in the service manual (or in a tutorial thread I wrote here years back, which I can't seem to find right now).

First of all, he asked specifically about analog synths and not SVF.

Ignoring those two points, I'm not sure which one you refer to, but if it's the one I wrote about a while ago, I've recently come to believe that you would be better served with this one which is just "delayless" discretization of SVF using TDF2 integrators.

However, I strongly believe it makes sense to keep this thread on the topic of analog synth filters not based on SVF.

What about the Steiner-Parker Synthacon's filter? No notch filter, but has BP, LP and HP inputs, not outputs.

http://en.wikipedia.org/wiki/Steiner-Parker_Synthacon

http://www.cgs.synth.net/modules/cgs35_syntha_vcf.html

Searching for non-usual filters I just found this: http://www.korganalogue.net/korgother/DL50Delta/KorgDeltaSer vice.pdf

Based on a quick look it's a 4-pole OTA cascade where the resonance feedback goes to the "ground side" of the 1st and 3rd capacitor.. it's got a switch for LP (that routes input to first stage as usual) or BP that routes the input to the resonance path so it probably qualifies as a multi-mode. No idea how it sounds.

That sounds like a fun filter!

Wow, very interesting! Never heard of those synths before. I listened to some clips on the net, both filters sound very promising. They didn't specifically show off the bandpass/highpass though, so it's hard to tell anything in that regard.

Richard

The most awesome sounding filter , those original units are so rare . Never quite heard any of the Synthacon filter clones hit the spot . Love to hear it done right in software.....

@Richard , check out the Dual Wasp filter :

http://www.youtube.com/watch?v=Rgc-4BFsNbc

That's a SVF.. though granted it's an unusual implementation.