I’ve been enjoying Polyphony recently and starting to create more patches using it. I couldn’t find a patch demo of MIDI Polyphony including Envelope and VCA, so I put one together:
Any other Polyphonic patching tips out there?
I find it useful to use the Sum module to convert back to non-polyphonic mode as soon as I no longer need to process each individual note. It saves a lot of processor and gives you more options.
Great. Thanks for the suggestion. For this patch, I’ve now added a Sum and plugged the Filter LPF into it.
I know this is a very old thread and hope that it’s ok to respond to it this far down the road.
I’ve been working on developing a “new-user’s” understanding of polyphony this week, and I’m really happy to have discovered this brief exchange. It’s been a big boost to my grasp on the matter (while still leaving a mystery or 2 for me to unravel).
As I say, I’m new to VCV and have my work cut out for me getting up to speed with all it offers and involves.
As part of that, I was myself exploring polyphony but had no luck deriving my “expected result” of getting multiple pitches to sound in response to the simultaneous press of 2 or 3 keys on my MIDI controller.
In my attempts I was sure to select the desired MIDI-CV Polyphony Channels setting, and that I was using modules that supported polyphony.
However a number of different patching exercises and experimentation with Polyphony Mode settings too all gave the same result: only a single pitch was sounded at a time no matter how many keys I held down.
So I read up a bit on synthesis polyphony in general and what I came across indicated that (insofar as I was able to understand the article) true polyphony seems to have been a “big ask” – in the analog hardware realm, at least – requiring an extensive support structure of dedicated oscillators, octave dividers, VCA’s and so forth, per key!
I asked some friends who use hardware modular rigs, and they pretty much said “Oh I have enough I can do with mono, I don’t really get into polyphony like what you’re talking about.”
From these I adopted the thought that the usefulness of VCV “Polyphony” must somehow also apply to other results or processes that produce or enable results that are different from just “more than one pitch at the same time.”
But then I found this enormously illuminating post and immediately decided to replicate the patch as illustrated, which leads to the point of this long-winded submission:
I can’t swear to having replicated the illustrated patch with 100% accuracy because some of the multiple-connections were a bit hard for me to trace, and some of the modules in the original look different now or don’t exist (I couldn’t find VCA-2, for example). So I guessed that this patch was perhaps developed “pre-Rack 2.”
But I got as close as I could, with the same result as before: only a single pitch at a time regardless of how many keys are pressed.
This led me to conclude that something was incorrect about my patchwork, and I was about to go back and trace everything out once again when I took a shot in the dark and added the Sum module as suggested by AlanF.
Holy cow! Harmony! Dissonance! Whatever you want, up to 6 simultaneous pitches at a time! A happy result, but once again – not the expected result.
Because – the way I interpreted AlanF’s suggestion – the addition of Sum was only intended to save on system resources, and not cause the sounding of multiple pitches to occur. So far as I understood jdev’s original post, the illustrated patch should have produced the “expected polyphony” I had imagined even without Sum.
So I’m sure I got something wrong at the get-go, and I’m going to go back and retrace, with Sum removed, to see if I can derive the multiple pitches that way.
It’s been a very interesting exercise so far though, and I just wanted to thank jdev & AlanF for making something that was on the way to seeming all but impossible a real, working thing. (The “understanding it all” part will have to be my next project! 
)
Asking a question of my own post, my understanding of VIZ, after reading its manual, was similar: That it also doesn’t cause polyphony to occur, it just helps you visualize the operation of the channels in use. Am I wrong about that?
My own previous attempts to achieve (what I call) polyphony didn’t have VIZ instantiated, and maybe that’s why, or was one reason why, I wasn’t able to sound multiple pitches simultaneously.
…Or something… o-2k
Maybe you read this allready:
Please share your patch with us, so we can check what’s wrong or missing.
I did indeed read that chapter (that’s partly how I formed my preconceived notions of Sum and Viz).
But I’m still at a level where concepts of a basic nature are at times very abstract for me, and some of it didn’t quite stick on that go-round.
Generally, it isn’t until I “just start trying stuff” that the intellectual material slowly (verrrrry slowly) gains a foothold in fact for me.
o-2k
I will endeavor to do so! In order to achieve that, I will need to “undo” some subsequent modifications I made however, and dial the patch back to the state I described.
I’m leaving for a few weeks on the road, so if I can’t address your kind offer prior to my departure I will attend to it upon my return.
Thanks so much! o-2k
The default patch when you run VCV without doing anything is polyphonic.
That’s true, and IMO the default patch is also a good starting point for people who are new to VCV.
The original patch is indeed for Rack v1. Below is close to the simplest possible polyphonic patch for Rack v2, wich might help diagnose your poly issues.
simple-poly.vcv (6.9 KB)
Select the correct audio interface in the audio module and now you should be able to play polyphonic notes on your computer keyboard. When that works you can, in the MIDI-CV module, substitute for your MIDI keyboard/controller and see if that works too. The Viz module is useful for seing whether you have pressed 1, 2, 3 or more keys.
When you place a new MIDI-CV module in a patch it starts out in monophonic mode. If you want polyphony you right-click the module and select the “Polyphony channels” and then the number of poly channels you want. In my example patch I’ve selected 8.
Also on the right-click menu you’ll see the “Polyphony mode” menu item. This concerns how the pressed keys are distributed for the selected number of poly channels. The Viz module is useful for seing the differences between those different modes.
Let us know whether it works with your computer keyboard and your MIDI keyboard.
First of all, thanks to you all for helping to get me up to speed!
In fact, while working to restore my reported “problematic patch” back to its replication of jdev’s original to share with you, I think I stumbled over the solution.
Once again however, I’m not sure I correctly understand the solution – why it works, I mean – but I will relate what happened:
Restored patch to my original replication of jdev’s illustration
The problematic one-pitch-at-a-time behavior returned.
But I then realized that there was also a limiter at the end of my array (just before the Audio module) which was not included in jdev’s original example patch. (I’m a cautious sort; I’ve arranged to instantiate a limiter as part of my default template to catch any unintended spikes. And my next question will along that line, concerning audio square waves – but that’s another story.)
In any case, removing the limiter produced the expected result of multiple simultaneous pitches. So jdev’s example was of course right all along, and I’d almost gotten there on my own.
As I tried to imagine a reason for the now-successful behavior, it struck me that the same scenario might explain why the addition of Sum to my first attempt also produced the expected result:
IF – as I now begin to guess – polyphony is related to multi-channel voltage (and, I suppose, by extension multi-channel audio, if the signal is routed out of, say, one of a polyphonic audio rate oscillator’s wave outs) – then the Sum module would squeeze everything down to one channel, and the whole thing would get passed to the limiter’s output because that single channel doesn’t exceed the “limitations of the limiter” (2 channels).
So the way I figure it now, the limiter (being two-channel?) might actually reject any signals appearing on channels numbering above either of the two it has which (considering the current configuration of Polyphony = 6) would prevent four channels of pitches from being recognized.
If that’s all something like true, then I also think I know the source of my own under-informed confusion but I’ll spare you all that burden as it’s embarrassing enough to reserve.
For me, it’s always the simple things that confound that old over-skull lightbulb, and this instance is no exception.
My confusion around the reference to the word “channel” shows my failure to appreciate fully that, what leaves the MIDI > CV module – even if it’s a gate or a trigger signal – isn’t MIDI any more!
And if that’s really the case, then the channels referred to in the Viz manual – the information it’s displaying – must be voltage channels, not MIDI channels.
As obvious as all that likely will be to many, believe me – when you’ve worked in the multitrack / 2-channel domain for as many decades as I have (with no experience mixing surround either, I confess) – even basic concepts like these require a bit of extra consideration. For example, it never occurred to me that each pitch would require a “channel” (which is my current impression – but you all can certainly correct me if I’ve got that wrong too.)
I don’t know if there’s a “Stereo Sum” module which could bring multiple channels down to 2 (left / right) outs, thereby making the full range of pitches available to the 2-channel dynamics processing that eases my nervous constitution (some of the patches I’ve managed to come up with can be pretty… unpredictable. Not necessarily in an uninteresting way, but… yikes.) So I should look for one.
But then, a module of that nature would actually be a complicated business because it would probably also have to accommodate some form of panning for the pre-consolidated channels, and now we’re talking about a special kind of mixer as well, really.
Yes, you understand correctly and this was likely your problem. As you say, polyphony in Rack simply means “a multi-channel signal”, and if you introduce a monophonic module after a polyphonic module, you break the polyphony and only get the first channel through.
In the modular world, you work inside a synthesizer. Usually at the end the audio is summed to mono, and after that you will apply stereo effects.
If you want stereo right from the oscillators, use Surge XT VCOs. Here you can have polyphonic CV input signals (e.g. coming from a MIDI-to-CV module) and a stereo output.
In the hardware modular world, cabels can only transmit monophonic signals, so if you want to play a triad chord, you will need 3 VCOs and 3 VCFs and 3 ADSR envelopes and 3 VCAs and so on. In VCV Rack we have cables that can transmit up to 16 channels simultaneously. If we want to achieve this in the hardware world we would need patch-cables that look like this:
or this:
Always keep in mind that in VCV, some modules can handle polyphony, some not.
I recommend watching the videos from @Omri_Cohen
This is all very generous and helpful – thank you!
OK - your explanation of the cable behavior provides is a very substantial establishing fact that I wasn’t in possession of (not that I wouldn’t love a real Eurorack of my own).
And it explains a LOT – I now see how the form factor informs much that Rack 2 is based upon, while also illustrating how flexible Rack is because it offers the option of handling polyphony far more easily if you want to go that way.
Right – and because I did not appreciate that polyphony = 1 channel per pitch, it didn’t occur to me that something like a limiter would restrict the number of pitches to a number matching that of its own channels.
In the hardware world I’m more accustomed to, a dual-channel limiter can limit lots of pitches through its 2 channels.
When I wrote
I failed to see the error in this thinking: I can’t imagine a mix in which I would pan the individual notes contained in a single chord! (A bit challenging for the listener, no? 
)
I suppose there could be a case for “internal panning” with the kind of synth that offers multiple voices.
But for any other scenario, I take the advice to apply stereo effects or whatnot at some point in the patch after the elements have been summed in some way. In my customary environment we wouldn’t really consider that to be the same as true stereo, you’re only just “stereo-izing” a mono source, but it does serve to spread the sound out in a nicer way.
This entire, fascinating digression stemmed from what was originally supposed to be a very fast, “what if?” experiment on my part. I wasn’t intending to get all bogged down in hearing a triad!
But it has brought me to understand a few very core & essential concepts, and I appreciate you all for being so generous with my “early learning” limitations.
Even though I might very well end up taking a page from my hardware modular pals and return to exploring more deeply the monophonic world, there’s never anything wrong with having a better idea of “what’s going on in there.”
Plus I got to see that totally hilarious photo of a “T/R/R/R/R/R/R/R/R/R/S” Connector – you sure don’t encounter one of those every day!
All the best, o-2k
Traditionally, synthesizers are mono. Modern synthesizers mostly have stereo effects built in. In this case, the mono signal from the oscillators will be “stereo-ized”. In the modular world, we soemtimes/often do the same. IMO a mono sound source with a bit of stereo delay and stereo reverb gives a good sound 
This foto is a fake I made using Gimp 
but here’s an existing module that allows 14-channel polyphony in the modular hardware world: A-180-9 Multicore
[addendum off-topic]
In the late 1980s and early 1990s I spent some time in recording studios (small ones) and everything except drum overhead was recorded in mono:
And in the mix session, stereo-FX was added, so no “true stereo”, only "just stereo-izing”. But it sounds great!
I’ve chosen to mix selected tracks in mono on occasion… when the mood is right. Release them on 45 RPM vinyl (properly mastered, of course) and they get even better!
(And at this point, it is perhaps worth appreciating the fine distinction between “monaural” and “monophonic…”)
0-2k
