Favorite Filters

Assuming you mean in the opamp or transistor feedback path…

My recollection of the Feedback Control Systems course I took in college is a bit rusty, but I’m pretty sure filter feedback operates on a timescale that makes it difficult to make interesting. If anything, it might make the most sense in a semi-modular, noise-hacking environment.

In a delay, the feedback path is recorded back into the buffer to be played again later. In order to hear the fed-back sound the next pass, the buffer has to be sufficiently long – at least one wavelength of the shortest period you can hear (tens of microseconds), but in practice, usually a few orders of magnitude larger than that (tens or hundreds of milliseconds).

In a filter, the feedback path is part of what defines the cutoff frequency and resonance, and the signal is “recorded back into the buffer” at the rate of electrons (speed of light). Any component you add to the feedback path, resistors, capacitors, etc, will change the frequency response, possibly throwing the filter into instability (oscillation), or unexpected (undesired?) output…

Anything beyond a passive electrical component, like a whole other module, seems like it would wind up turning the “filter” into either just an amplifier, or some kind of unpredictable EQ.

On topic, I’m likely going to give the Erica Polivoks DIY VCF a try; seems slightly more tame than the Harvestman, but from what I’ve heard in youtube videos, it sounds nice… Anyone else given this one a spin?


Can i get some recomendations for complex resonators/filters in small hp?

Right now i ve a u clouds wich i use only as resonator filter, without striking it, just sending through audio. I like it but i would much more enjoy an analog response and sound, yet with the ability to add lots of overtones up to giving an effect of adding voices by resonance. Not sure if its clear what i mean.

I did enjoy 3 sisters a lot when i had it, but too expensive and not available, i used it mostly in formant and traveling through the filter-interaction, so a multi filter with sich control is my thing.
I do enjoy diy. The vibrazum 2 seems interesting but to large and costy.

What about those bandpass filterbanks like ems and doepfer do they offer such kind of multi-voice-feedback resonance singing for lack of better description?

The Serge Res EQ made by Random Source might work well. It isn’t small at 18hp but it has ten bands (spaced in sevenths) that can either attenuate or emphasize frequencies. It can be set to self oscillate, it can mix two inputs, and you can split the bands into parallel combs. I think it hits “feedback resonance singing” very well.


Seconding this. Just a beautiful module.

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Thanks for the suggestions the RS is indeed much too large i am afraid, even if i kick out the 8hop clouds.

What do you think about the rocinantes gate?

I think thats a tempting package but i doubt the resonance can sing the complex filter way.
On 3.08 min i am not sure if thats the resonance or the waveform itself that starts appearing as overtones
Ideally i am looking for a diy similar to 3 sisters

It’s not inductor based, and not exactly small, but the ADDAC 601 Fixed Filterbank sounds excellent and is packed with an effing ton of features. It sounds excellent fed back on itself, the resonance is sort of dusty sounding and it saturates really well. I use it as a drum voice sometimes by pinging it and feeding various band outputs back into it, you can sculpt a really wide pallet of sounds with it just by doing that alone. Inverting the envelope outputs and sending them back to their own bands turns the thing into an 8 channel multiband compressor too which is really cool.


More ADDAC love - I’ve recently got a 603 triple bandpass and while a little sensitive (mini pot for res, grr) it is wildly flexible. I’m considering two and could see it as a QMMF-4 replacement, plus some.

My longest standing fave is the Macbeth Dual SVF. Was lucky to get one from someone selling a very large system, and the way it resonates just glues itself to the sound and always seems to add something subtle and lovely.


That ADDAC603 looks so cool–do you have any examples of stuff you’ve done with it? I’ve been hoping to hear more ever since it was announced but the ADDAC demo is still all I’ve been able to find.

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Still learning the ropes. I’ll surely have a demo thing soon…


I also recently got an Addac 603–really incredible filter. It has so many useful features from the overdrive/gain staging, plus cv control over (most) everything, phase switch, and inputs/outputs for each channel. It’s a sleeper of a filter–my serial # is in the 50’s–but it adds a lot to any system—sound design, EQ, plus all the cool stuff you can normally do with multiple band pass filters.


filters very underrated.

Now that I have a total of 7 analog oscillators with the ttsh, banana synths, and atlantis, I kind of want to make a 4u 84hp rack of just doepfer/ ladik filters + resonant equalizers with a format jumbler, passive mixer, and some LPGs on the 1u row. I guess I have 8 filters across all of my modulars already, I didn’t even realize…

I think my favorite overall is actually ripples, but it’s hard to say. All the filters are the best filters D:


  • Sisters
  • Ripples
  • Atlantis
  • TTSH


  • Phenol (LPF, BPF)
  • Synthacon
  • 73 vcf

Twin Peak filter/resonator by rob hordijk, love the versions of klangbau koln and epoch modular.


I searched the thread but haven’t found any mention of the ALM Mum M8 yet. I’m looking at both it and the MI Ripples because their built-in VCA is very useful in my small case. This is mainly for classic subtractive synth duties.

I do love the “Roland-esque” sound so the Ripples is really appealing. It’s just easier for me to buy the Mum M8 locally at the moment (shipping is a major PITA for me with no current fixed address).

I like that the Mum M8 has a unique topology, and it sounds great in the demos. But most of them are based around it filtering drum loops/samples/wavetable or FM type sounds, and that’s just not the main thing I need right now. I’m sure I will end up with both eventually but right now I need to pick one.

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I’ve been a bit obsessed with that since it came out just due to the asethetics and concept, (screws in a little bag with aciiid smiley is a nice touch :smiley: ) and the surprise at the time that Mumdance made a module and was getting into increasingly synth/noise stuff. Never going to able to justify buying it any time soon tho :frowning:

Only briefly tried it once at a synth meet so and never tried Ripples so don’t really have anything helpful to say on that

I think Ripples is super underrated; can squelch like a 303 but also stay tame but also self oscillate but also cut the amplitude to zero (something the mum m8 can’t do).


I have a Mum M8 and like above, it’s mild on simple analog waves. Definitely much more suited to filtering audio from either a sample or something complex. I tend to only use it with Plaits, it’s quite nice with Plaits chords. I’ve been on the fence about swapping it for Ripples since they’re the same hp, but I do keep it around because it’s nothing like my other filters (3 Sis and VCF-74). When I was recently using the Mum M8 one thing stood out about it, it’s very mixable. Like, to go off on a tangent, when I was playing lots of guitar in high school metal bands, I made the mistake of trying to have this huge sound. I could never understand why I didn’t stand out in the mix. The Mum M8 has that kind of restraint that sounds mild or weak in isolation, but tends to set nicely in a mix.


Perhaps because I’m “not a filter person”, my favorite filter is Filter 8.
Its base sound is a smooth Roland-like filter tone but the main benefit of it is how it expands the utility of a filter into more realms than cutting frequency content out of a sound source. It can do oscillator, LFO, glide, weird CV waveshaping, etc.
I end up using it in basically every patch I make.


Fave is Sisters. I am also loving the QPAS. Can be used in a straightforward manner as a stereo LP/HP/BP filter (or 2 mono ones) or it can be a crazy glitchy stereo percussion machine just by patching triggers into it to ping it:


I second the QPAS love. It can also be really cool resonator once the VCA gets set. Plus feedback patching opens up all sorts of fun.

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Thank you both!! This is exactly what I gathered from the demos. I’d still like to get one for that purpose, because I really enjoy the plug-in version (of the Akai filter it’s based on) and use it a lot to warm things up. But it definitely sounds like Ripples is the way to go for me right now. And lucky me, Control is getting them back in stock soon so I don’t have to wait long!