Mannequins Three Sisters


Hmmmm anybody else have trouble with the trim procedure on this? My Sisters is flat as hell, drops by about a semitone per octave. I tried trimming it but the screw was already at the max, I can only make it flatter…


as an aside, I happened to patch Three Sisters and Mangrove as a layered voice last night and they stayed in tune together for the whole range of the piano!

@smbols, you’re probably doing everything right but just to check: you’re monitoring the low output?


Which out are you using? Only the low is meant to track 1v/octave.

(Edit: wasn’t awake enough to see @alanza had asked exactly the same thing.)


If the screw is at max, turn it back to the middle and use a sequencer to change octaves during the process. You’ll be able to see the accuracy of the tracking.


In case you haven’t seen it, there’s a calibration guide here. If it’s flat at the top of the range, you actually turn the trim pot to make the current pitch flatter - it moves the 0v frequency flatter than e.g. the 2v frequency, so you are actually spreading out the range from 0v to 2v.

As @Jonny suggested, you want to choose an arbitrary root frequency for 0v, send in 2v, check to see if the new pitch is 2 octaves above, if flat, trim flatter, if sharp, trim sharper, then send 0v in again, tune 0v back up to the root frequency, send in 2v, trim again, rinse repeat.


This is great! Thanks for sharing. I’m going to mine this afternoon to try and replicate


Okay, that makes sense. Thanks for explaining what’s going on. That guide is a lot more helpful than the blurb in Sisters’ dedicated manual.


Okay so a few things going on with my 3S that I’ve been meaning to ask about for a while now. Most likely not anything ‘wrong’, just need some clarification on what exactly is going on…

If the frequency of the filter matches the frequency of the oscillator being input then I get a volume spike on the low output (span fully CCW, quality at 12:00). This seems to mean I can’t get a fully clean filter sweep as whenever the frequencies match it overdrives for a very brief moment?

Similarly if I am using the high output, when the frequency of the filter matches the oscillator frequency it seems to overdrive and very slightly low pass filter the signal. Which again makes a clean filter sweep impossible as at some point the signal spikes.

My suspicious is that this is because the 3S is always slightly resonant no matter what the quality is set to? Looking forward to seeing what any of you think though, thanks in advance!


I don’t have a concrete answer for you, but it sounds like your oscillator is pushing the filter into resonance.

What is the effect when you put Quality less than 12:00? Are you using crossover or formant mode?

Also, which input are you putting the oscillator into? I find that if you put it into ‘ALL’ and listen to LOW, that will give you the standard low pass filter. Same with high pass, input into ALL, listen to HIGH. There will be spikes otherwise, I think.


In both instances I’m inputting to ‘all’ and then going out from ‘high’ or ‘low’ in crossover mode.

I’ll have to test changing the quality lower than 12 tomorrow to be sure, but I’m pretty sure when I was testing earlier it didn’t remove the spike. I’ll give it another go though!

For reference I’ve been testing with the square, tri and sine output of the Instruo Ts-L.


I don’t have a 3S, but maybe try attenuating on the way in? You’d still get a volume spike but you could stop it from overdriving.


short and sweet 2 module patch. love what I’ve seen of this new Bizmuth module (


That is totally insane!

Any idea on a price or US availability?


Perfect Circuit had it for $90 (sold out yesterday as I had it in my cart). love that every jack is an I/O


Watched this a few times, wow. I might have to put that on my short eurorack wishlist. May be a lot of fun in my Mannequins skiff with Teletype.

It also has me thinking I need to do some feedback experiments with just Sisters and Cold Mac or Sisters/Cold Mac/Walk.


I got my new mangrove yesterday and I decided that for once I’d use the 3S as a proper LPF/LPG. What I discovered is that it’s not simple at all. I used the classic multimode filter setup: quality at 12, crossover, input in all, monitoring low for low pass.
I can get to silence with frequency ccw, but as I turn the knob up it gets to a point where it boosts the oscillator frequency nearly up to distortion, and then, passing 12 o’clock, it starts loosing all the low frequencies and and becomes a sort of high pass. Is it supposed to be like this?


I got yesterday the same “problem”, first time using 3s as LPF to filter my new (and noisy) music thing modular Spring reverb , i supose is by the “character” of this module, is easy to go Wild with It.


Sounds similar to what I was describing a couple of posts up. I’m still trying to work out if it is just the ‘character’ of the module or if I’m totally misunderstanding something. As much as I love it for all the weird patching you can do, it is kind of frustrating that what should be the most basic feature is not working as expected.


@beforeitwascool just in case: if the switch is set to formant, the low output is a bandpass at that quality setting.

fwiw I think the resonant “boost” is definitely something my units do even with quality at noon


Have any of you tried putting white noise through your Three Sisters and looked at an FFT scope to see what’s going on? I’m going to try it out tonight and see what I find with mine. I haven’t noticed any unpleasant distortion on my module.

Maybe one of you could post a clip to demonstrate? I’d also be curious what your Mangrove settings are.