MCabinet questions

[Dewdman42]

New MCabinet user here. A couple questions....

1. Can the EQ graph be explained a few things. What are the blue and red curves? Left and Right? If so, then what is the single black curve line? Also what is the grey area surrounding the overall curve? Also what are all the colored vertical lines on this graph, obviously some kind of spectragram, please explain what I'm looking at.
2. Same as above for the IR graph
3. The resonators and wideners...are they static in nature or dynamic? There is mention about "randomness" and that we basically hit the seed button to randomly generate a "seed", but then what happens while processing audio? Are the resonators fixed at that point unless changed by the controls or a new seed, or is some kind of playtime dynamic processing happening, even if randomly?

[imrae]

People are saying "static" like it's a bad thing, but guitar cabinets don't generally change shape significantly while you're playing them. The key word should be "linear". Resonators are linear but *do* create noticeable effects in the time domain.

[Dewdman42]

Can you elaborate a it on what you mean by the resonators create effects on the time domain?

[Dewdman42]

So I think I figured out the black curve line is the existing "profile", either saved or recently imported from IR's. The colored curve lines represent further changes currently active above and beyond that saved profile. That would be from Resonators, Wideners, the Cabient smoothers, etc. But apparently the EQ changes are not reflected there, not sure why not. I do not know what the grey wide curve line is exactly.

Regarding linear vs non-linear cabinets, I don't want to start any kind of passion war about whether cabs can be or should be non-linear or not, or whether even if they can its too small of a difference to matter, etc.. But I am just curious what is currently possible with MCabinet in terms of non-linear responses.

The dynamic EQ can obviously provide some playtime non-linear response, which could be interesting, but I am not too knowledge about what some interesting and realistic things would be to do along those lines that would make sense for a guitar cab. Any suggestions welcome. Also wondering if there is anything else that MCabinet can do while processing audio in a non-linear way beyond the pre-calculated EQ profile.

Please clarify this if I'm wrong, but it seems to me that the EQ profile can be pre-calculated based on non-dynamic EQ, the smoothing functions and some other things, it seems to me like the resonators and wideners are also pre-calculating a resulting EQ profile curve based on the settings also, but its not entirely clear to me at the moment. But the dynamic-EQ obviously has to respond in a dynamic non-linear way to the actual audio and can't rely on a static EQ profile to do what it does. Does anything else in MCabinet work in a dynamic way like that? Not including the modulators, which I will ask about later. What about the harmonic filters? It would be interesting if a saturation module was also included for non-linear adding of saturation, unless that is possible now?

Someone mentioned that some time domain things can happen as a result of the resonators in some way, but its not clear to me how that would work if the resonators are pre-calculating a resulting profile to apply linearly. But maybe the resonators are doing something more while processing audio?

thanks for your responses...

[jmg8]

Please explain briefly the difference between linear and non linear.

[Dewdman42]

for who's sake? mine or yours? I know what it means. Dynamic-EQ is not linear. Is anything else in MCabinet non-linear?

[Dewdman42]

@jmg8 here you go: https://www.tokyodawn.net/meaning-of-sy ... roduction/

[jmg8]

For my benefit. I started to read the link you gave me, but I do not have time. That's why I was hoping for a brief explanation.

[Dewdman42]

think of linear like its something that can be predicted ahead of time and a simple map created that can turn incoming values into outgoing values. For example, IR's are linear. Its just a big EQ curve. Audio comes in, look at each band, lookup the amount of EQ to apply, done. Non-linear means the output may vary depending on other factors...for example, Dynamic-EQ, compression, certain kinds of distortion, etc.

That is probably a vast over simplification...but hopefully you get the idea.

IR cab tech is basically linear. Real speakers are not linear, because at certain levels they can start to breakup and resonate and other funny things that aren't captured or represented in a linear IR. Many arguments on the internet about whether this is significant enough to care about for guitar cab work.

MCabinet goes beyond simple basic IR tech though. The built in dynamic-EQ, for example is non-linear. I'm not sure what happens with the resonators and wideners, though I'd like to know. I'm not sure what happens with the harmonic filter built into the EQ also. and anything else that is non-linear in MCabinet...and further from that...what would make acoustic sense to play around with for realistic or semi-realistic dynamic speaker simulation.

[jmg8]

OK. Thanks.
So something you can try is the analog parameter in the EQ. It creates non linearities. If you want to introduce these non linearities without changing the EQ shape too much, you could try setting one of the EQs filter type to allpass.
Just an idea.

[imrae]

Can you elaborate a it on what you mean by the resonators create effects on the time domain?

I mean that strong resonances will ring out so you perceive them as a "time" event rather than a "frequency" event. But because resonance is linear it can be encoded in an IR, or as a (sharp) frequency response.

All-pass is also linear, by the way. You can see the IR here (the figure numbers are reversed in the text) https://www.uaudio.com/blog/allpass-filters/

[Dewdman42]

Right well first let’s clarify that IR processing is linear. So if we export an IR from mcabinet to use elsewhere then it will be linear.

Now the question is what mcabinet does differently then typical IR processing such that the results can be non-linear. Dynamic eq and compression obviously is. What about the resonators? I’m not talking about perceived ringing and things that SEEM non linear. If the resonators are simply changing the eq curve to add peaks and valleys around resonate frequencies, then it’s still very much linear and would export out completely to an IR for use in an IR processor. However if there is more to the resonators such that they are doing non linear things when processing sound in mcabinet, then that’s something else. I wish the author would clarify what the resonators and wideners are doing in terms of all that. All we have to go in is there are unnamed algorithms and dice buttons to generate new random seeds, whatever that means.

Additionally I’d like to understand to the harmonic section of the dynamic eq and whether that has non linear potential. Then of course there is the modulator which is not only non linear but has potential for time domain changes but I’m not sure where that fits into typical guitar cab simulation

[imrae]

That's right. Dynamics processing, saturation and modulation effects care nonlinear and cannot be captured with a regular IR. I would assume that those sections are disabled during export, but it would be nice to hear it from the dev.

Long resonances can absolutely be captured by IR processes in a linear way; you can have resonances in convolution reverb if you like. It may be that not all resonant tails will make it through MCabinet's IR exporter due to limits on the sample length - would need to experiment with that.

[MeldaProduction]

That's right. Dynamics processing, saturation and modulation effects care nonlinear and cannot be captured with a regular IR. I would assume that those sections are disabled during export, but it would be nice to hear it from the dev.

The dynamic EQ will be included in the IR export, but it will become static. Hope that answers the question

[Dewdman42]

That sounds reasonable but anyway regular eq and dynamic eq are not quite the same because of the non linearities. What about resonators, wideners and the harmonic filter?