Evil Twin - Dual Oscillator FM/PM/AM Synth

@Joe and myself have had an immense amount of fun building this synth, and @odevices has been very kind enough to review it for us and has given us his seal of approval!

So, without further ado, I hereby introduce Evil Twin, a Dual Oscillator FM/PM/AM Synth that you can download, and literally just assign a gate and V/oct input and go… In no time at all you’ll be making what we think are very nice FM sounds indeed.

Full details on how to install and use this custom unit are available on the WIKI page:


Here’s an overview diagram:

Enjoy :smiley:

Here’s the patch:

Evil Twin.lua (90.9 KB)

And a few presets I made that show what is possible with this little beastie. All respond well to short triggers, explore the full range of the V/oct input to find the sweet spots:

Evil Twin - Clavi.lua (92.0 KB)
Evil Twin - Electro Pop.lua (91.7 KB)
Evil Twin - Finger Mouth.lua (91.8 KB)
Evil Twin - Low Down n Dirty.lua (91.9 KB)
Evil Twin - GlockenKnock.lua (91.7 KB)
Evil Twin - Robot Bass.lua (92.2 KB)
Evil Twin - Metal Mallet.lua (91.5 KB)
Evil Twin - Shit Piano.lua (92.2 KB)

I should close by saying that though I have posted this, @Joe has been just as involved in this process and deserves full credit. Neither of us would have produced this on our own. @Joe - it’s been a pleasure and an honour as always :smiley:



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Holy coooow. Can’t wait to try this!

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How did you collab on this? Sharing chains back and forth?

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SICK :sunglasses:

Love the work you guys did on the diagram as well. Won’t be able to try this until the weekend but am looking forward to seeing what people post in the next few days. Thanks guys!

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Yep, just exchanging the LUA file. We may both need SD card socket replacements soon. :rofl:


Excellent work guys!!! Will definitely check this out.


I can’t believe this. I am speechless. Can’t wait to be home tonight. Thank you @anon83620728 and @Joe
My 301 has chosen the perfect time to arrive in my hands. :smile:

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How’s the CPU usage like?


18% as it is, 13% if you bypass the wavefolder. (I’ve just read the docs :sunny:)

Ah. Was a bit too hasty, missed the documentation – thanks!

EDIT: looking at the diagram, this is absolutely bonkers :smiley: Can’t wait to dig in, and I warmly tip my top hat to you gents, can’t imagine the amount of brain this has required.


Oh wow! I was thinking of building myself a little FM custom unit but there’s no way it would have been this feature packed and well thought out.

Thanks so much guys!!


Oh nice, I just woke up to all this, thanks for the comments and likes everyone :smiley:

Yep, that SD card started to feel heavy once or twice :joy_cat:

I just looked at the discussion me and @Joe had while working all this out and there are 270 messages. To be fair @Joe did a lot of the leg work actually patching it up, I was smashing and breaking it as much as I could, finding problems and we both came up with solutions all the way through the process. This eliminated a lot of versioning problems because the files were generally going one way.

I really mean what I say about neither of us being able to do this individually, it really was a team effort. We’ve worked together on quite a lot of things over the years and have established an excellent rapport, considering we have never actually met in the ‘real world’ I think we’re doing alright. @Joe wrote almost all the documentation, I drew the graphic and converted the docs to the WIKI.

I think the biggest challenge was to get the gain staging across the whole patch right, but we think we have found a nice balance with reasonable constraints.

I’ll say again, we loved every minute of working on this … Thanks @Joe you’re a star!!


Adding additional instances of Evil Twin seems to carry a non-linear CPU increase. You can run two instances with no problem. If you disable the wave folder on two of them you can run 3 and still have a little room left to add some supporting units (more ADSRs, etc). The UI gets a little sluggish in certain spots with 3 running, but still workable.


Thank you !!!

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Thank you and congrats, very nice custom unit.

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Thanks again everyone :smiley:

We’re going to put together a larger bank of presets for this, so if any of you make some nice sounds, even if using additional units we would love to hear them.

If you post the Lua file we’ll include it in the WIKI patch pack - do your best/worst :slight_smile:

Also love to hear any recordings made using this too!

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Got to have a play with it this morning- really nice, thank you!

Btw, I’ve not downloaded the presets as I wasn’t sure where to put them on the SD card?


@SpikedLunch, really you can put them anywhere you want. I might recommend:


Then you can insert an empty custom unit, go to it’s menu and select “load preset”. It should default to this directory so that you can just pick the one you want.

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Thanks Joe!