Multiband Spectral Resonator / Custom Unit

Hey, dawned on me after watching Neil’s vid No. 8 and wondering if possible…has anyone put together something resembling a multiband spectral resonator using the custom units and a thick weave of ladder filter chains all tuned to specific freqs + Q? not quite sure how to route it all yet but slowly going to give it a shot… maybe something resembling the Verbos Bark Filter / Make Noise RxMx / Frap Tools Fumana?


I was trying to piece together a vocoder with the 3 band EQ and the Ladder filter. Ideally you’d want a bandpass filter. I couldn’t get the EQ to have a tight enough band and the ladder filter didn’t really work either. If we had a bandpass filter, we should be able to do it. It sounded cool and kind of etherial like the SMR but all the bands let too much through and I couldn’t get the separation between the bands.

Audio in -> Band pass filter -> VCA -> band mixer
carrier in -> band pass filter -> ^

Each pair of band pass filters should be identically tuned.


Cool idea guys hopefully we will get a band pass unit in the future.

For fun I gave this a shot, and like @auxren says, you can’t get a tight enough band with a combo of EQ and Ladder Filter.

Sounded kinda neat though!

I based Video #11 on this attempt.

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Hi Neil, not sure it’s worth it’s own thread so continuing from here…
Any clear or quick suggestions about best method to use the 301 as a quadraphonic mixer?
Going to give it a shot this week but a little foggy on how to route and re-route to get a pan cv that would sweep through a pair of stereo outs to give you something approximating quad?

I haven’t tried it - but - one idea is you could setup out 1-2 as L-R Front and out 3-4 as L-R Rear.

Then - put various VCA’s on both chains and you could set it either an external CV signal and tweaks the gain/biases for the desired front to back control, or perhaps use internal envelopes and CV processing sitting on a global chain?

Nice! Thanks… I’ll give it a shot this week. Missing my Koma Poltergeist lately and was thinking with some clever internal routing the 301 is capable of similiar and beyond.

I just did a test -

Although i have only stereo going to my main system I can still confirm it works. I was using a Doepfer Joystick as an X/Y signal test.

So -

Stereo Global chain as signal source

Ch 1/2 and 3/4 each set to stereo

Simple test with a VCA placed in each 1/2 and 3/4 chain with the inputs of the chains set to the global chain.

The VCA pan is the X, the Y is the Gain. with bias at 0. The 3/4 VCA gain was set to a negative amount to work backwards in behaviour.

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AMAZING. A beautiful thing. Thanks (again!) for charting the way. Very excited to patch this up in the coming weeks when there’s an opportunity to use quad. The latitude of aptitude nascent within the design of this module staggers.

SO I made a 16-channel digital set of filters, modeled off of Fumana today. RIght now it’s just LPF, and 15 BPF at different set frequencies modeled off of Doepfer A-128 frequencies with odd channels panned left and even channels panned right. Going to try to add envelope followers etc tomorrow but here’s a quick vid of the results

Funny, I just did something similar and posted it yesterday! Er301 and Sweet Sixteen fixed filterbank patch


I actually saw your video and it gave me the idea! Did you do envelope following yet? That’s next on my list.

i dont think im going to, not sure i would use envelope following all that much.
that might be cool if you had another set of 12 bandpass filters and had the first set of 12 filters/envelope followers modulating the second set of 12. then you could do volcoding/spectral transfer.
but im already at 70 some % CPU with mine, with the filters, mixers and vca’s for just one set of 16 so i dont think it could handle that.

One thing i would like to add though is spectral tilt as in the fumana and verbos filterbank.

A-128 looks interesting, more bands in the very low freqs. for mine i used the freqs from the buchla 296.

Oooh. I should try that model too.