So I am looking to buy a synth that will be used partially for monophonic sounds, and also polyphonic sounds. I have a lot of history with modular where I am used to doing lots of feedback CV patching (taking filter audio output to control filter cutoff, or using an oscillator for filter FM) and want to have this type of capability in a synth with multiple voices. My ideal would be to have each oscillator and filter as a source in the modulation system, so I could control any parameter with it (I am primarily thinking things like filter cutoff, waveshape, PWM, etc). To pair with this, I want a modulation routing system that is quick and intuitive to be able to quickly create complex patches, preferably with lots of performance control with velocity sensitivity and mod wheel stuff. So these are the synths I have seen so far which seem to do this sort of thing.
Sequential Take 5
This synth has the filter output, and the oscillator 2 output as modulation sources and can be routed to any of the destinations, and is probably the closest that I have seen to what I want.
ASM Hydrasynth
This has the mutant system, which allows you to do FM modulation, but it is not clear to me if you can do more freeform patching, like filter output to modulate oscillator waveshape.
Novation Peak
This can do some FM modulation, but the extent of it isn’t really clear to me, and I don’t think you can freely use oscillators or filter output as modulators.
Elektron Analog Four
This can do some FM and cross modulation between tracks, but isn’t really a poly synth. The LFOs can be key tracked and go into audio rates however so that gives lots of potential for audio rate modulation. Also I think it could be interesting taking the audio output of one track and feeding it to the CV input of another. But that would be strictly monophonic.
The question I have not yet been able to answer is whether this is actually worth anything in a polyphonic synth. I love this kind of complex audio rate modulation in modular, but that is usually monophonic, and it might just get to be a big mess doing it polyphonically. Then again the DX7 does an absolute load of audio rate modulation and is known for poly sounds, so I think there is a lot of potential there for new and interesting sounds. Does anyone have input on these ideas? Any synths I am overlooking? I don’t care so much about analog vs digital, except that I do want to have sharp waveforms like saw and square and a resonant filter (Digitone is my only polysynth and I’m not loving it all being based on sine waves)
It might be worth looking into the Arturia Polybrute. Its LFOs can go from one cycle per 50 seconds up to 100 Hz. You’ll have to check to see if you could route a normal oscillator to another for faster audio rates (I’m not sure if it can do this).
The modulation routing system looks fantastic, but looking at the manual I don’t see any oscillators or filter as a mod source, so not sure if it will do what I am looking for. An audio rate LFO is nice, but 100hz is a little low, and I would want it to track the key I am pressing so that the sound is consistent across the keyboard, which is why just having a normal audio oscillator as a modulation source is really handy.
Check out the other Sequential synths too, the Prophet 5 has oscillator B as a mod source, Rev 2 has synth audio output as a mod source, and I believe the Prophet X has the oscillators or samples as a mod source as well.
The Argon8 (and maybe other synths in the 8 series? I can’t recall) have a polyphonic LFO that can track the pitch of the keyboard. Probably not quite what you’re looking for but maybe worth investigating (time-stamped example from Loopop’s review). I had one for a while. I rarely regret moving on from gear, but this is one of the rare exceptions where I think quite often about getting another, for whatever that’s worth.
Take 5 is great for modulation and can get dirty with audio rate stuff, but the FM is exponential rather than linear (or the other way around?) so can’t really do proper melodic FM type stuff.
Dreadbox Nymphes (6 voice analog) has audiorate lfo’s (also polyphonic and key tracking). I really like the modulation system on this one. I’m not so fond of the shift button interface.
The Hydrasynth probably isn’t what you’re looking for but the 2 CV ins are freely assignable in the mod matrix so it would combine with your modulars quite usefully.
Generally I would say that it doesn’t pay off to pay a lot of money for a polyphonic instrument, which provides very complex modulation facilities for single voices - this makes it expensive - and then overlay all those voices to get pad sounds or the like.
IMO layering many complex and individual sounds leads almost everytime to a mixed sound as we know from choirs. The individual voices will be melted to something new and much of the individual character will be lost.
For me a rule of thumb is to have monophonic synths for complex sounds and polyphonic for less complex sounds. But I had the option to get both.
If there is budget for one synth only, I would recommend to check out the polybrute. The mod-matrix is very close to modular and very quick to understand and to use.
A curveball option is the gotharman zaturn. It’s properly modular, but offers poly. You could also look at digital Modulars on the computer as they can often do poly (and are cheaper).
I’m a bit confused by your mention of dx7 when you already have a digitone?
I worked on complex/chaotic feedback networks (CFM) in analogue modular for years, did a paper on it for my undergrad, and the simplest way to find out if those techniques are going to give you what you want is to do it in software.
I found that doing complex feedback FM with poly turns into a massive mess personally, it’s exponentially harder to control and you end up having to minimise a lot of the crazy stuff to get anything that isn’t sheets of noise. Polysynths require less harmonic content to be effective in general, and chaotic feedback can generate harmonic structures that take up more space than complex chords on a poly anyway.
I’m not saying you shouldn’t pursue it, but maybe temper your expectations.
I did have a lot of fun doing it, but and I guess you will do, but once the sonic novelty wears off you’re left with a major investment in time and equipment that’s not really expressive at all, and can tend to noise at increased levels/layers of feedback, as this pushes a feedback system into hyperchaotic behaviour. It’s not as interesting as it sounds.
What I did end up finding very useful was sampling interesting monophonic sounds and using those as the basis for poly patches, the dense harmonic structures that come from CFM can do interesting things in that context.
Play around before you drop a ton of cash, and I’d be interested to hear what you come up with during your investigation.
Edit: added a couple of spectrogram images of six-operator chaotic feedback loops to show the harmonic density
I just mention the DX7 (and digitone too for that matter) as proof that complex audio rate modulation is still worthwhile in a polyphonic instrument, I just suspect that you have to be judicious with its use and tend towards harmonically simple waveshapes.
You can also crank the LFOs into audio rates, and many parameters can be taken further than you would expect by using multiple slots to modulate the same source and destination.
You can do tons of audio rate modulation on the Super 6. Envelope 1, osc 2 (naturally) and both LFOs can go audio rate. The only issue is the depth is limited on some parameters like the VCA (though this may change in a forthcoming update—but never buy something on promised features).
You can still make plenty of wild sounding feedback FM noises on a Hydrasynth if that’s the sound you’re going for, but you can also do pretty standard FM poly stuff as well.
There is a point though with a lot of stuff where less is more. A simple sound can easy translate to 8 or 16 notes but a complex sound can be pretty busy even at 2 or 3 and start to clash a bit.
I’m adding this image just as a point of interest, two similarly configured chaotic feedback systems (in this case the same 6-operator feedback loop made of Schmitt-trigger oscillators) even with different component values and set at random input values will eventually sync up and output similar signal. This weird behaviour is described by Steven Strogatz in his book Sync, very interesting imo.
