MPowerSynth FX Questions

[dmbaer]

I’ve been spending some time recently seriously trying to understand some fundamentals about how the FX module interaction is implemented in MPowerSynth. I’ve got some questions, and this is probably only the opening salvo. This is one hell of a powerful beast, but learning to do effective FX design is not an easy undertaking.

The factory FX presets stick to pretty conservative goals. For example, there’s only one use of the LR/MS conversion capability and what’s being done isn’t very interesting at all. There’s a Matrix module available that is a total mystery since there’s no example of its use that I can find anywhere. I suspect that this situation is that the preset developers largely have not learned how to really take advantage of the power here. So, if others want to pile on to this thread and add their FX questions, then that would be welcome.

So, getting started …

1 What’s going on with blue connecting lines vs the usual black ones? What does the blue color designate?

2 The LR to MS conversion module seems to direct output to two lower modules on two tracks if such are present. Is this a stereo signal going to each receiver module in which both channels are the respective M and S signals? Or is it a stereo signal with L or R null? Or is does it just get reduced to mono signals? What’s actually going on?

3 There are a number of delay presets that have three parallel delay modules on three tracks (and nothing else going on). The “height” (row placement) of the three modules varies from preset to preset – sometimes they’re lined up in a row, sometimes the row placement is lower or is higher as we move from column 1 across to column 3. I’m assuming the placement of the delays vertically is completely irrelevant to the result and we’re just seeing the whim of the preset designer. Is that assumption correct?

4 It took me a while to figure out that “Sidechain” in the context of MPowerSynth FX really means a signal that will become part of the audio and not something controlling the audio (such as we’d think of it the context of a compressor sidechain). At least this seems to be the case with the Ratio module. The sidechain signal in that case is one of the two signals being “ratio-ed”, right? So what’s going on with the other Ratio module, the one that has two sidechain inputs? A related question is whether there are some cases where “sidechain” is a control signal and not a signal which ends up as part of the audio stream (i.e., as in the compressor example cited above)?

5 I could not find (or maybe just missed) a use of the LFO module. To what purpose can an LFO module be employed? I don’t see a way to use it for the traditional modulation applications that LFOs are normally involved in.

That’s probably enough questions for now.

[MeldaProduction]

Got it . You know this is just a beginning . I'd eventually like to make lots of video tutorials myself, but since I have about 0 minutes of free time these days, it has to wait .

Ok so:

1. Blue lines are side-chains . It's simply for effects having multiple inputs. Despite it is pretty obvious which input is the main one (it's on the left), it's still good to make it even more obvious.

2. LR->MS creates 2 tracks, one MID and one SIDE. Both are actually stereo (just to keep it simple, simply put, all processors in the grid have the same configuration), but it doesn't matter, only channel is relevant. So if you do some hardcore stereo expansion on say MID track, it will be stereo, MS->LR convertor will ignore the unused second channel.
So, don't overthink it .

3. Yes, it's irrelevant .

4. Sidechain input is nothing else than an additional input. The meaning has NEVER been strictly to "control the audio somehow". It's simply secondary input and its rather obscure name is coming from ancient analog times and now we are simply using it because everyone is used to it. But can do anything. For instances, MVocoder somehow merges the 2 channels to produce the output. It can even switch the input and sidechain input.

5. LFO is actually essential for creative purposes. The modulators themselves of course provide pretty much the most versatility you can ever get and can control anything, but they have 2 disadvantages:
- Take more CPU
- They are processed by blocks - the Settings/Settings Modulator protection basically says how often the modulators are processed. For example, the typical "High" (3rd option) means, these are updated every 32 samples, hence the plugin is processing 32 samples with the parameters unchanged (some are subinterpolated etc., but generally it's just not that accurate). Of course, 32 samples is less than 1ms and you can even use "Extreme" option to get 1 sample perfect processing, but that will take lots of CPU.
LFO FX on the other hand is sample perfect and takes almost no CPU. Of course its possibilities are way more limited as well. For example, you use it to drive RatioSideChain FX, so to kind of "autopan" between 2 track. Or you can post-process it somehow and multiply it with the original audio to get a "custom autopan". Or even more typical - you can use it to drive Filter FX. All of this can be done with modulators with much less effort, but most of these simple scenarios can also be done using LFO FX and the accuracy will be better + less CPU usage.
One extreme usage scenario - imagine you want some complex modulation, something really crazy, based on input, multiple LFO's somehow merged together, changing in time... You cannot do that even with modulators if you think of something too complex, or it would be just too complicated, modulators modulating modulators, crazy s** like that . So you can actually generate something like that using LFO FX, envelope followers and stuff like that, and then generate Feedback channel. But don't actually create Feedback FX, kind of "send it nowhere", and don't let it get to the output. And here's the thing - you then use a modulator in Follower/Envelope mode and use notice the Feedback input - modulators can listen to the audio input, MIDI input and also feedback. Now I'm thinking it's possible that MPowerSynth actually has this hidden, will check it out and add it potentially.

[dmbaer]

Great answers - that I mostly understand. By the way, I'm using MPowerSynth FX as the basis for this discussion, but you may have figured out my real interest lies in MXXX applications. Now, if I may ask further ...

LR->MS creates 2 tracks, one MID and one SIDE. Both are actually stereo (just to keep it simple, simply put, all processors in the grid have the same configuration), but it doesn't matter, only channel is relevant. So if you do some hardcore stereo expansion on say MID track, it will be stereo, MS->LR convertor will ignore the unused second channel.
So, don't overthink it .

Of course, I'll try not to overthink it.

Just to nail this down, though, let me see if I've got it straight regarding single vs dual LR to MS signals and back again. The one place in the MPowerSynth FX presets in which MS is used has an LR to MS module feeding a single Distortion module feeding an MS to LR module. Everything is in one column and (absolutley not overthinking it) it seems reasonable that the input to distortion is M and S rather than L and R. The input to MS to LR is the same and the output is back to L and R.

Now, if for some reason we instead had two distortion modules side by side, LR to MS would create two outputs, one going to each. The Distortion modules would do their normal thing (not knowing or caring that the two stereo channels in the signal were the same). The MS to LR module would receive two inputs, one from the distortion module in the same column and the other as a sidechain from distortion module in column two. When a sidechain signal is present, the MS to LR knows to ignore the right channel of the primary input and use the left channel from the sidechain input in its place.

Have I got that right?

For example, you use it to drive RatioSideChain FX

By this, do you mean the module called Ratio by Input? If so, I assume the first sidechain is one of the signals being "ratio-ed". Then does second sidechain become a modulator to contol the ratio setting? That makes the most sense, but if you could confirm, that would be comforting.

Or you can post-process it somehow and multiply it with the original audio to get a "custom autopan".

Aha ... maybe this is starting to make sense. You're talking about using the Math module, correct? I didn't see any examples of that in the MPowerSynth FX presets either, but I believe the fog is lifting if that's one use of Math.

envelope followers and stuff like that, and then generate Feedback channel ... modulators can listen to the audio input, MIDI input and also feedback. Now I'm thinking it's possible that MPowerSynth actually has this hidden

Well, as I said earlier, I'm just using the MPowerSynth FX capabilities as a proxy for MXXX. I'm expecting that MXXX will have ability to use MIDI inputs as well at some point. If you need to hold that aspect close to the vest, I'll understand.

One final question (for now, anyway ). It occurs to me that the Modular module has the potential for creating a situation of unchecked recursion where a module preset directly or indirectly includes itself. I have not bothered to set up a test since it's easier to just ask if you've got protections in place to prevent that happening.

Sorry to be a pain with such detailed questions, but hopefully others will also be benefitting from deeper understanding.

[MeldaProduction]

OK so:

1) LR<->MS - I'm totally lost there . Please do NOT think about channels there. It's the pipelines that matter. LR->MS gets input from one pipeline and creates 2 of them, the one on the left is mid, the right one is side. (I'm not sure that's what you meant, but it looks like that).

2) Ratio with 2 sidechains - confirmed . Sorry for the misnaming, internal identifiers .

3) Math module - it's kind of experimental, I was just trying to come up with examples and that's the first one that came to my mind . Anyway there will hopefully be examples & videos about that eventually. Math is basically some kind of basic mathematical operator - it takes 2 inputs and merges them with basic math operations, or it can also do some more complex calculations. The multiplication between 2 signals I was talking about is especially useful .

4) Modular FX - it cannot recurse really. Well, you can load modular with submodular, but when you think about it, one can never create a scenario in which it would clone itself inside itself infinitely , if that's what you mean. Main point behind Modular is that you can simply have some "subprocessors", or sometimes the 4 pipelines may just not be enough to make something simple enough .

[Breeze]

These are great discussions but it's clear that MPS is such a complex work in progress that Vojtech has little time to fill in all the missing explanations in the documentation. Sometimes the only way to figure things out is to set up mini experiments to test and confirm behaviours, but that can be very time consuming.

One thing that would help is using common terms for things. In my experience "Side-chaining" is pretty specifically used to describe compressor use of a VCA control source coming from another source than the input. Otherwise they're really just other "channels". Perhaps things are different in Vojtech's experience and environment. Using that term the way it has here threw me off too.

[MeldaProduction]

Breeze, as I explained, the term came from it, but let's say you have ANY audio plugin having 2 inputs in your host - in 99% hosts it will be called a "side-chain", whatever the purpose is. The term is off, that's for sure, but people are used it. Main input is main input, secondary input is the side-chain, whatever it is supposed to do. Check my example with the MVocoder above if you are still unsure.