ER-301 complex oscillator test


So, I tried to create some sort of complex oscillator arrangement on the ER301.

My knowledge about complex oscillators is not too extensive, so consider this just a test.

I put a sample player on channels 1 and 2. After setting the 1v/oct and gate routings, it was just a matter of setting the modulations:

  • Output 1 to modulate the V/Oct of channel 2’s oscillator, and vice versa (Exponential FM?)
  • Output 1 to modulate the speed of channel 2’s oscillator, and vice versa (Linear FM?)
  • Then I set a variable slew on channel 2’s 1V/Oct stream (simulating DPO’s follow circuit)
  • Finally, I patched in a Mutable Warps in the final output (boo, this is cheating!) I would’ve used the 301’s Fold unit, but I wasn’t completely sure how to get the most of it.

I recorded a little video of me wiggling the patch. Sounds nice! A DPO it isn’t (it seems like the more extreme ranges go into glitch/noise territory, whereas the DPO just does this extraordinarily weird tonal dance when pushed to extremes).

A more clean result would’ve been just to create a ‘mod index’ oscillator – a sine wave that tracks in step with the oscillator, and that can be used to dial in modulations. But I specifically wanted to see how the ER-301 handles crazy FM feedback type stuff.

Any corrections to my patching, comments etc., just shoot :slight_smile: All in all, I’m pretty surprised by how capable the 301 is in this role, too!

(In the video, I first patch the linear FM, then some exponential, both alone at first. Then it’s an FM free-for-all, with some enveloped wavefolding from the Warps plus some follow circuit emulation thrown in.)


Sounds cool! Certainly not a correction, but for some additional fun, I’d recommend enveloping the amount of FM you’re applying and drive it with the same gate as your amp envelope. IE control the FM amount over the duration of the note. That’s how I like to get the best out of some of those extremes.

I was a little confused by the Fold unit myself. I thought it might kind work like the analog fold on the Shapeshifter (saw one in your rack too). But it has more controls. I fed a straight sine wave into it and wiggled the controls around, and watched it on a scope, and it started to make a little more sense.


Nice one!! This is a great idea, I messed about with feedback in the FM stuff earlier in the year but never thought to complete the patch in this way - totally obvious now you mention it :smiley:

I keep meaning to revisit the FM stuff now we have global chains, perfect for self patch feedback FM operators.

There’s loads of attenuation options on the DPO, not sure how far you’ve gone with this aspect of it, but it always opens up loads more possibilities.

What @Joe said about the oscilloscope too!

I don’t think Warps is cheating :wink:

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Hey @josker

I was wondering how’s this going, making any progress? And are you planning on releasing this as a custom unit?

Cheers :slight_smile:

Hey there! :slight_smile:

I actually got inspired by your nudge – I cleaned this up a bit and made it a bit more understandable.

One question, though – it uses global chains and two channels, how does the process of sharing it go? Should I share it as a quicksave? There’s Q1 thru Q4 with the suffix .LUA in the relevant quicksave folder – do I just put them on here?

I tried to include the MOD INDEX of the DPO in this simulation, and it almost made my brains stop working, so there might be loads of mistakes. Also, I can’t remember if FOLLOW does anything when there’s a 1V/OCT patched into both oscillators on the DPO, so that might be wrong.

To do: Include waveforms other than sine.


Awesome :smile:

Honestly, if it’s that complex you’re thinking of a quick save as the best way, I don’t know, maybe @odevices can help?

Yeah, it’s possible that the MOD BUS would be perfectly doable without global chains, but I can’t figure out how that would be done. The entire thing is four sine wave oscillators and a ton of VCA’s, but it is spread pretty wide to get the BUS working and each osc on its own out :slight_smile:

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I guess you could just try a quick save… what’s the worst that could happen? :smiley:

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Exactly :sunglasses: will do ASAP



I have precious little time right now, so I thought I’d just post up the quicksave – it’s not even that far along, so the expectations would just get inflated otherwise :slight_smile:

So that’s a quick save folder, you want to rename the folder according to which slot you want it – hope this works!

There might be more clever ways to do this, but this is my first draft, the best it can be with this brain :slight_smile:

I simulated the FM bus behavior of the Make Noise DPO. Notes from DPO’s manual:

“The internal FM bus is hardwired for SINE wave in both directions and makes use of the Normalization Switch found on the mini-jacks, so with nothing patched to the Linear and/ or Expo FM inputs the associated attenuator sets the nal index of FM applied to each destination. As you increase the Index Level, the Ampli-tude of VCO A Sine Bused to VCO B Linear FM and Expo FM attenuators is increased. At the same time the Amplitude of VCO B Sine Bused to VCO A Linear FM and Expo FM attenuators is increased. Therefore you could have dierent amounts of Linear and Expo FM in BOTH directions, all at once. At greater than 90% Index, all of the FM bus lines (Linear, Expo for both VCOs) go into overdrive when the associated attenua-tors are set to beyond about 80%. The FM overdrive combined with the Bi-Directional Dynamic FM results in some extreme Circular FM capabilities. These sounds will get out of hand quickly. The key to controlled FM within the DPO is attenuation since setting the Index to 100% really does push the circuit to its limits.”

Mine really isn’t that sophisticated, but I do have two MSIN oscillators as global chains that allow similar things to be done.

The FMBUS global chain is just a place for a knob to be assigned - it controls the FMBUS amount.
V/Oct also as a global chain, because it needs to be mapped to two global chains and two tracks at once (or not, if you like!)
Then there are LIN FM and EXP FM for each oscillator as global chains - simply placeholders for offsets, map them as you like.

So basically,

Take EXPFM1: it controls the amount of MSIN2 being fed to the V/oct of OSC1 on track 1.
LINFM2 controls the amount of MSIN1 being fed to the linear FM input of OSC 2 on track 2.

FMBUS controls a ‘master’ VCA that allows any modulation at all to happen.

There’s a ‘FOLLOW’ control on OSC2:s custom controls, which is basically just an envelope follower control – rough rough emulation of DPO’s ‘follow’ circuit.

Hope the files load, and hope I can make at least some sense of this.

It’s fried my brain, but it’s been fun already :slight_smile:

EDIT: To clarify - the reason for the MOD oscillators as global chains is that the DPO has normalizations which make the sine oscillator the default FM source for every direction. If I were to tap this unit’s FM modulation from outs 1 and 2, it would be the same as patching the FINAL OUT to each FM input on the DPO. What difference does this make right now? None! But it’s future proof: adding, say, saw oscillators to tracks 1&2 won’t contaminate the FM.


Hey @josker!

First - thanks for sharing this!

Second - sorry for taking so long to check it out. I know when I post some kind of discovery to the forum, I’m eager to get some feedback, whatever it might be. :slight_smile:

Finally, and, sorry to be dense - can you give me some basic instructions on how to get this going? I found the V/O connection to A1 in the global chain, and connected that to my keyboard.

But I’m not so much getting any sound out of it. There are some very low frequency sin waves (maybe not quite LFO but very low) coming out of OUT 1 & 2. I assume I’m supposed to be connecting up some external oscillators to some of the Ax-Dx inputs? I can’t quite figure it out though. And should I be monitoring OUT1, OUT2, or both?

Ahh…now I feel better. I had trouble extracting the kinds of sounds i was expecting and thought it just my obtuseness!

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Sorry! I feel like I kind of left this project stranded. I just had a performance yesterday, which allows me to tear down my patch, and hopefully even make a small video of this!

@Joe – the sines are pretty low, but I think I set a +2400 offset to them to make them higher? If not, that’s what you can do, just remember to set the offset to oscillators both on channels 1&2 and the global chain MSIN oscillators (If that’s what you want, of course.)

After that, you just need to make five assignments to the Global chains: LIN FM 1, EXP FM 1, LIN FM2 and EXP FM 2 and the FM BUS. I just used simple CV offsets from an Erogenous Tones (ugh) Levit8 (groan).

After that, dial in, say, some EXP FM to both oscillators, turn up the FM BUS and you should start hearing things :slight_smile:

@sixnon – I’ll do my best to get this thing explained soon :slight_smile: It’s not you at all, it’s the patch and my poor explanation!

I think it’s definitely a good deal me :wink: I’m oft agog at the amount of detailed, academic synthesis knowledge on this forum, and unsurprised that my capacity to understand detailed explanations sometimes lacking!

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Think I got this all hooked up right and had a wiggle with it this evening. I see what you mean about it getting kind of temperamental and going into some pretty noisy territory pretty easily but there are definitely some sweet spots.

Nicely done. Good fun, thanks for sharing! :slight_smile:


Knowing what I do of your musical history, and without discrediting that in any way, it’s great to hear these tentative explorations into noise - there’s some really nice sparkly bits (to my ears anyway) in there :smiley:

Totally random and completely unrelated composition exploring really annoying timing shifts and fails - I love this crap, a kind of happy and drunk vibe, think 3am after an epic lock-in:

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