Arturia Forums
Software Instruments => Modular V3 => Modular V3 - Technical issues => Topic started by: Tausendberg on October 21, 2016, 03:18:15 am
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Ok, simple experiment, you take a sawtooth oscillator and output the same sawtooth oscillator twice to two of the mixers and then link them together and output them into VCA 1. Predictably what happens when you adjust the mixer output is that they essentially just cleanly adjust the amplitude of the signal because they're in phase, they're duplicate signals basically, and so it's just more energy in the waveform.
But something I just noticed, while intending to mix a filtered oscillator output with an unfiltered oscillator output, is that if I take an oscillator and directly connect it to the mixer and then I take the same oscillator and put a second output through the default low pass filter and then put it to a 2nd mixer input and link it, I can clearly see on my oscilloscope (with the lowpass filter completely open) as I adjust the mixer levels between the clean and filtered that even though the source signal is the same oscillator just duplicated, the mixed signals are visible and audibly out of phase relative to one another.
I don't know if this is a bug per se, maybe a slight alteration of the signal's phase is some kind of byproduct of the DSP, but it would be nice of Arturia to perhaps put in some code to align the phases of the oscillator outputs when a single oscillator has more than one output.
Incidentally, I can connect two outputs of an oscillator to two low pass filters and then put the outputs back into two mixer channels and the signals are in phase again.
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I just did some further experiments...
There is good news. I just tested all of the filters including all of the settings on the multimode and they all shift the phase by the same exact amount so all I need to do is run one duplicate signal through a fully open low pass filter and the other duplicate signal through any filter I want or mix and match and they'll be in phase, not an ideal solution cause it costs me one of three filters, but it works.
There is a limitation to this trick though, apparently if you run a signal through more than one filter (osc 1 > Filter 1 > Filter 2 > Mixer) Then each filter applies more phase change and so you don't have enough pass through filters to offset 2 or 3 filters' phase changing in this manner.
Did a little further testing and apparently mixers can also cause phase change. (Sawtooth 1 > VCA 2 :: Sawtooth 1 > Mixer 2 > Mixer 1 > VCA1) and I can see when wired up this way that the signals are out of phase.
I don't know how big of a deal this might be to some people but the way I see it, part of the advantage of using multiple outputs from a single oscillator is that they will be perfectly in phase and this quirk (don't know if it deserves to be called a bug per se) does complicate things.
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In case anyone is wondering, I just tested it and the mixer shifts the phase by a slightly different amount (apparently slightly less) compared to the filter so I don't think the mixer can be used as a perfect offset for the filter unfortunately.
Update:
Alright, so, after a bunch of experimentation, long story short, the main filter module shifts the phase of the signal slightly more than, apparently, every other audio processing module including the formant filter, the filters on the noise module, the ring modulator, and the mixer output. What that means is, to compensate for the phase shift of a main filter module, you need to use another filter module and all the other modules can be compensated with any of the other modules.
Arturia, if you're reading this, if you could somehow streamline or remove these phase shifts entirely from the VST, that would go quite a long way to simplify things.
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Are you sure it is'nt a sync behavior you get and have? Perhaps a sync issue?
How do you read/ see the phase issues in your scope?
Is it all waveforms or only when using Saw you see issues?
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Ok, I've added a couple examples of very simple patches in addition to oscilloscope images.
It clearly shows how if I make two outputs from the same exact sawtooth wave, one going straight into a mixer channel and the other one passing through a low pass filter and then to a linked mixer channel, the oscilloscope shows (and one can hear) that the signals are definitely not in phase. See what I mean?
While in the second image, if I have two outputs from the same oscillator and run them each through their own filter, and then back to the mixer, they both end up being in phase again.
This phase issue happens with all of the waveforms, not just the sawtooth.
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2nd image
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"dusted off" Modular V2 to see if it also had the same problem.
Apparently it does.
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Thanks for the images.
On your images i see some kind of sync behavior.
What do your Phase meter tell you about phase? (Another plug-in.)
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Oh, I never used a phase meter...
So you would say it's actually a sync issue?
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way interesting discovery!
It makes sense as you suggest the software may impose some latency to the start time of the cycle.
Maybe Arturia could, in future, have a setting that when ever anything goes through a filter (or whatever causes this delay) to delay the other audio sources' cycle start ..or force the delayed wave 'back to the left'... ...like some DAWs can do to compensate for latency .e.g 'force waveform cycle sync' ?
I bet this is not quarantined just to Modular V.
There are a few other issues that I suspect may be related to the cycle starts of waves shifting around unpredictably. Matrix has some odd, perfectly in tune behaviours that I bet have got something to do with wave cycle starts...but I am no tech and am only guessing.
cheers jb
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Oh, I never used a phase meter...
So you would say it's actually a sync issue?
Your Phase meter show pure mono in phase it looks like.
You can read about how to read the Phase meter in Studio Ones/ your DAWs manual.
Well - Perhaps i would'nt call it an issue at all. More a sync behavior. You get the same behavior if you hard sync 2 OSCs.
In the combinations where you don't get a sync behavior, i think you would get the same result raising the volume for one OSC, if the sound in each input is identical. But one can wonder why there's no sync behavior in those cases, but in others there are a sync behavior.
You know i have written about Sync in some threads. I can't tell if sync may give some phase issue. But i would not say, this at first hand has to do with phase. It's a sync behavior.
See the illustrations on page 93 in Modulars manual.
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BTW: For the SAW waveform in an osc you get the same sync behavior using the PW parameter. That i have written about here -
http://forum.arturia.com/index.php?topic=88045.0
- as i see some troubles in this.
I also think using sync can thin out the sound like for instance in MINI V too. If this has to do with phase i can't tell.
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Ok, but it's not that the signal are out of sync because of the PW/Wave Shape setting, all of the oscillator wave shapes do that.
The signals appear to be out of sync because the modules put them out of sync, regardless of which oscillator is used.
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Ok, but it's not that the signal are out of sync because of the PW/Wave Shape setting, all of the oscillator wave shapes do that.
The signals appear to be out of sync because the modules put them out of sync, regardless of which oscillator is used.
Yes i know. I just tell you that a sync behavior ALSO appear for a SAW wave, if you just use PW. Just like you also get sync when you hard sync 2 OSC's. Check it in your scope.
Check the manual as i wrote. That part has nothing to do with PW just like all the reat of my comments did'nt.
Please read my posts again more closely. I'm not at any point claming your testing has to do with PW.
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Sorry, maybe there was a misunderstanding.
All I'm trying to do is to suggest that this out of sync behavior of duplicated signals shouldn't be happening.
For instance, in Reaktor Blocks, I can duplicate signals from an oscillator and run it through filters or any other modules and the signals remain perfectly in sync.
I'm bringing this up because, I mean, I never noticed this exact issue until I examined it closely, Arturia might not even be aware of this bug.
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It's great you bring up things.
I'm just saying it's a sync behavior, similar what you can read about in the Modulars manual page 93.
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but it's a sync behavior that shouldn't be happening, I mean, there's nothing about analog technology that would cause a signal when passed through a low pass filter to be delayed by some amount.
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As you can see in my posts, then i wonder about why it sync in some routings, but not in others, just like i have explained.
I can't say for sure, if it's a exspected behavior or not. But i wonder about the difference.
I can add - If i recall correct, then you for instance can take two outputs from the same waveform, and pass each of them thru a filter, then combine them in the mixer, and you don't get the sync. I guess that could be similar to the Reaktor example you mention.
EDIT: How come you can do this, but you can't do ithe same, when only sending one output thru a filter, without getting this sync behavior? To me that make no sense at this point.
Perhaps it has to do with using direct waveform outputs not using a filter.
But then why is'nt there the same sync behavior when combining 2 direct outputs from the same OSC waveform?
Somehow i think the filter among other things alter the pitch, like i suspect it do in MINI V and i guess in other V5 applications. And perhaps when using the same OSC waveform output twice that produce a sync behavior, when one output is direct and another use a filter. But i still wonder. And as i wrote, then i don't find the normal soft/ hard sync behavior to good, and in addition to that i also find there is a problem with having a sync behavior added to the PW for the SAW that even have a different octave at minimum and maximum. That make it impossible to use a normal SAW and another waveform from the same OSC together using the same octave and/ or without having some kind of synced SAW. EDIT END.
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I mean, really, I think every module that the signal goes through delays the signal ever so slightly and that's what causes the out of sync effect.
If I take an oscillator output and split it with one osc going straight to the mixer and then another signal going through two more filters then I can see that it's been delayed even a little bit more than it would be if it went through one filter.
Let me demonstrate...
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Ok, so, as an extreme example, I split up the signal at three different points and then mix all of the signals back into the linked mixer channels and you can clearly see how there are now four oscillators out of sync relative to another because each time a signal passes through a filter, it gets delayed just a little bit.
From what I've been able to research, this essentially shouldn't be happening, signals, in an analog synthesizer, that would be passed through multiples, wouldn't be delayed like this.
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Beside the below, then please refer to my other posts. I can only repeat my self, including what i wonder about regarding the behavior.
I think perhaps a issue can have to do with how pitch is handled somehow throughout some of the applications. This i have reported before in the forums,that i think needs Arturias full attention.
1. The results you called out of phase is a sync behavior, and not about something being out of sync or delayed as such, except perhaps from what for pitch differences may introduce. The sync we talk about is creating complex waveforms, but how this is achieved i don't have the technical knowleadge to tell.
Have you seen Modular V3s manual page 93, that i have refered to some times? Otherwise please do so.
(BTW - If you check Matrix 12 sync, then it's a bit different because it don't get thin, and don't change waveform before you change pitch of VCO 2. Change pitch upwards, and you'll see what you call delay, but is a what's called a complex waveform.)
A sync behavior is not a delay bug.
But i have never said, that there is'nt something odd or wrong going on. Actually quite opposite like you can see in my wondering in my posts.
I just wanted to find out, if what you reported actually was about some sync behavior going on, or was about phase like you was talking about. It is about a sync behavior and not about phase - (except - as i said - their perhaps are unwanted phase issues involved in pitch and sync behaviors in some V-colection synths causing thin sound). Then it's easier for Arturia to understand, what this is about.
2. This is just to comment your anolog comparison, and nothing else.
Analog synth signals are allmost intant i think. It's fast, but it's not at lightspeed, so there must be some kind of delay. We talk about digital computer stuff processed in series. There will be some kind of delay.
If you for instance in Studio One insert a effect on a track, then below the performance meter you'll see how much the signal is delayed. Not all signal delay is audioble - You don't hear it.
(Perhaps some day signal delays will be gone (or nearly gone), when we get quante computers where processing is'nt made in series.)
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I can add this too:
I do believe there is some kind of unwanted behavior - some kind of bug.
I think it might be about the same as for instance about this (Even if i posted this in MINI V3 forum):
TOPIC: STILL A NOT WANTED BEHAVIOR WHEN OSC'S ARE TUNED EQUAL OR SYNC IS USED.
http://forum.arturia.com/index.php?topic=87770.0
TOPIC: PITCH DRIFT AND OSC DETUNING ISSUE.
http://forum.arturia.com/index.php?topic=89175.0
Something unwanted is going on, that seems to be pitch related issues, and that might cause other issues like phase issues.
To me it's a bug of some kind, or more bugs or a vital construction issue, like i can suspect it is. As said, then i think Arturia should pay full attention to this, as it has to do with some of the most important things in the applications, namely the sound and the sound stability.
In the case of Modular and the experiment you show one can say, that in a analog modular you don't take more than one output from a single output, and that may not be intended to do in modular V, even if it's possible in some routings, and that difference also make me wonder, as i have written in my posts.
But you also get similar unexspected results. when doing things like you should be able to do.
I have explained in my posts. (Also in other threads).
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Just to report, as i have mentioned Matrix using Sync in this thread.
Sometimes when just tuning Matrix OSCs equal - (not using sync), then one get a sync behavior. It's not allways. This confirm it's something Arturia should give full attention.
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Yeah, I really think they should.
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I have been thinking a bit more about all this.
I think there actually are some kind of phase shift involved in all this. The sound it self is not out of phase, but the waveforms start at different points - and create a complex waveform that i think have a phase relationshift.
So something introduce this kind of phaseshifting.
I guess something like pitch/ pitchdrift and/ or some kind of delay like you talk about can do so. And as you say in this topics header, then it looks like the filter introduce this behavior somehow. And because of some odd behaviors i have exsperienced i think perhaps envelopes for some reason introduce phaseshiting relationship as well.
If this is the case, then i don't know if this actually can be seen as a bug.
In your experiment 2 outputs from the same waveform directly combined in the mixer do not introduce any phaseshift relationship.
However - Then this none phaseshift relationship behavior should also be seen when hardsyncing two OSC's to eachother, but that do introduce the phaseshift relationship even when the OSC's is tuned equal. This should then be wrong. And then this is the bug.
When tuning 2 OSC's equal then a pitch or phase drift may introduce the phaseshift relationship.
Having an option to not have the osc's be "freerunning" might solve the issues - at least what the OSC's are concerned. Perhaps one need the same "Freerun" option for filters and envelopes, in the cases where one use multiple outputs from a single oscilator.
Looks like Matrix is closest to be correct - if not fully correct taking the analog simulation in account - as Matrix do have the phaseshift relationship when having two osc's tunned equal, but not when the OSC's is both using Sync and is tuned equal.
But still an option to not have the OSC's to "Freerun" would be nice to have.
So looking at how Matrix do it might also fix things, if my thoughts in this post is correct.
There do seem some odd behaviors concerning pitch and other things as you can see in the threads i have had linked too in the thread. But it look like Arturia should be able to fix it all.
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https://www.arturia.com/mini-v/behindthemini-v?&utm_source=elasticemail&utm_medium=email&utm_campaign=mini-v_com_2016&utm_term=nl-halloween&utm_content=stefano-filter_picture2
I just looked at this article and in there they are talking about employing a zero delay filter...
Do you think that might have something to do with it?
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I did some experimenting tonight with oscillators syncing and I agree with what you say, the simplest solution would be for Arturia to just implement the Matrix's sync algorithm when on the Modular V the user chooses 'hard sync' and maybe to make the programming simpler, that could also turn off free running.
One thing I noticed today was that I took the triangle output of OSC 1 and connected it to Mixer 1 and took the square wave output, also of OSC 1, and connected it to Mixer 2, and it worked perfectly, the waves were completely in sync, like what I would expect from another OSC 'hard syncing' to another Osc even when it's perfectly in tune.
Right now when I use hard sync with two oscillators perfectly in tune with one another, what appears to happen is that at first it behaves like soft sync for a short amount of time and then it "snaps" into sync. What I think it should be doing with hard sync when the oscillators are in tune to one another is that they "snap" into sync as soon as a key is pressed or perhaps are already in sync before the key is pressed.
I know it's a crazy idea but some of these problems could be solved just by giving the user an option to reset the oscillators every time the key is pressed (I don't know if something like that ever existed in the analog world though).
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To put it another way, I can tell that Modular V's "hard sync" doesn't work like it should because I've watched oscillator sync being demonstrated on analog instruments on youtube and it's instantaneous and perfect, it doesn't 'drift and snap' like Modular V's "hard sync".
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https://www.arturia.com/mini-v/behindthemini-v?&utm_source=elasticemail&utm_medium=email&utm_campaign=mini-v_com_2016&utm_term=nl-halloween&utm_content=stefano-filter_picture2
I just looked at this article and in there they are talking about employing a zero delay filter...
Do you think that might have something to do with it?
I don't have the knowleadge to say yes or no.
I think in your exsperiment that show that the filter somehow introduce the phaseshift relationship, and regarding the envelope behavior i have noticed, that the fact it's not zero delay might be the - or a cause for the phaseshift relationship behavior.
I guess if a filter or a envelope changes the pitch a little, then that too can be a cause.
I really don't have enough knowleadge about this, and about how all those things works, to say for sure.
But something could and should be done better. Perhaps the things we have suggested.
I know it's a crazy idea but some of these problems could be solved just by giving the user an option to reset the oscillators every time the key is pressed (I don't know if something like that ever existed in the analog world though).
I don't think it's a crazy idea.
I don't know either regarding the analog world. But sync is possible in the analog world.
To me no matter what, then as long the original behavior is availble as good as possible, then i would say options can be added, especially if that option repair things or ass functionality.
As said - then something could and should be done better. Perhaps the things we have suggested could help somehow.
Also observations can help finding solutions.
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One more thought, something that just occurred to me, the oscillators should be synchronized, when set to hard sync, as soon as the connection is made, even before a key is pressed, because in analog the oscillators are constantly running even when the VCA is closed and so they're being forced into sync even when the VCA is closed.
That means for Arturia to depict hard sync authentically, when a key is pressed there shouldn't be any perceptible time that the oscillators aren't synchronized.
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I have just done a test on todays new update of Modular V3 version 3.0.4.1092, based on a thought to only listen to the synced OSC too -again.
As we agree, then 2 equally tuned hardsynced OSC's should not give phaseshift relationshift behavior.
And actually my test show, if only having sound from the OSC that sync to another, then the hard sync do work like i believe is correct.
But if you also have sound from the OSC you sync to, then it go wrong even though those two OSCs are hardsynced.
But why do a synced OSC suddenly be both in and out of sync with another, just becasuse you listen to both OSCs at the same time?
It's like there are two different signals running. The synced signal, and a none synced signal/ waveform that come out of the waveform outputs of the OSC another is synced to.
We have discussed some things that might can cause the phaseshift relationship behavior, when it should'nt. And perhaps also the mixer can cause the wrong behavior.
We have also mentioned some suggestions to what might can help solving the phaseshift relationship behavior issue, when it's wrongly introduced, - at least in some situations.
But if for instance the mixer, the envelopes, the filters and other modules introduce the wrong behavior, then perhaps more is needed.
I still believe Arturia should pat this full attention. And perhaps look at Matrix, even if i had a few times that it went wrong too, if i first just tune the OSCs equal, and then use Sync. But mostly Matrix work correct i believe. Matrix work better regarding this issue.
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Oh wow, I figured we were due for a Modular update, although I'm not surprised they haven't fixed some of the major issues...
Edit: Hmm, I just looked, it doesn't appear there are any functionality updates. Just a bunch of stability and small bugfixes. I really hope they fix amplitude modulation by the next update because in my opinion the amplitude modulation is the biggest problem with Modular V right now. In traditional synths, amplitude modulation is used in a large number of things and so it's ridiculous for it to be a feature that basically doesn't work well.
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I think the main issue is about when 2 or more OSC's is tuned equal and you hear at least 2 of the OSCs. Actually the issue can occour if a sound somehow end of where OSCs are tuned equal, even if it happens during some kind of modulation like a detune passing a eaual tuning. The sound become thin when that happens, and thatsnot good.
Also it's not good a envelope sync modulation clicks. Just listen to the template preset "Sync Env".
There is something very wrong as i hear it. It sound quantized instead of a smooth transistion. The higher the note the easier to hear.