FR: Volume Envelope for MCabinet

[MeldaProduction]

Of course it makes a difference! You are essentially trimming the EQ response by lowering the accuracy on the low end, which doesn't fit the IR anymore. Just try using the integrated EQ using some low-pass/shelf filters, you'll get something similar.

The point is, trimming the IR only produces inaccurate results that's all. Volume envelopes make sense on reverbs to control the tail, but here, it just does something "unexpected", that's it.

[Sascha Franck]

I completely disagree. For me there's nothing "inaccurate" in an IR. It's "what works, works". And no, it's a lot different compared to using an EQ as you can feel the "time difference" in your pick. And it's also not doing anything unexpected, more to the opposite, it does *exactly* what I want most of the time, namely getting rid of some early reflections which are often getting in the way of a tight sound.
As said, I'm using IRs for recordings since around 15 years already and once the AMT Pangaea (one of the first dedicated hardware IR loaders) popped up, I bought one for my live duties. And all through these years I captured my own IRs, mixed them and - well - edited their volume envelopes.
Also, pretty please, when it comes to MCabinet, you're not really trying to talk about "accuracy" of an IR, right? I mean, I really love it, but it's got not much to do with representing an accurate cab/mic IR.

Fwiw, I am right now inmidst of a larger IR experimentation phase, trying to fool around with more time based things, such as somewhat delaying certain frequecies. And yes, even a short IR of just 1024 samples at 48kHz gives you 21ms to fool around within, which is a plenty, given that most experienced players start to feel roundtrip latencies at something between 5-8ms already (some are even more discriminating). Also, once you've made some timing based tests in the lower millisecond domain (such as for whatever Haas effect experiments), you will know how much time-based frequency response alters our perceptions. Pretty much a similar technique (delaying certain frequencies) is used in the BBE Sonic Maximizer.

In a nutshell: Yes, it makes a *whole* lot of sense to adjust certain timing based aspects in an IR. And sorry, even if you are the developer, that doesn't necessarily make you right. I could happily supply an example of a trimmed IR (in fact, I already did, see my sound example) which you would never be able to mimic with just an EQ - at least not as soon as you actually *play* through that IR.

[imrae]

The formal equivalence between IR convolution and EQ is pretty much the entire basis of MCabinet, right? If you import your trimmed IR into MCabinet it should show you exactly what EQ curve is needed to mimic it.

[Sascha Franck]

Well, sure. But I don't want to trim my IRs destructively. And I never need to do that, either - because my IR loader of choice offers an envelope. I was hoping for MCabinet to offer such an envelope as well - and let's face it, shouldn't be much coding mystery or anything.

[Chandlerhimself]

MCabinet isn't really an IR loader, so this doesn't make much sense. Its actually closer to an EQ. When you import an IR it changes it into an EQ curve and then you can play with the curve in various ways. Trimming it or cutting is is equivalent to changing the EQ in some way. Adding more details and resonances increases the length and smoothing out decreases the length. An envelope would most likely just sound like an EQ tweak, but less predictable than using the already provided EQ.

[Sascha Franck]

MCabinet isn't really an IR loader, so this doesn't make much sense. Its actually closer to an EQ. When you import an IR it changes it into an EQ curve and then you can play with the curve in various ways. Trimming it or cutting is is equivalent to changing the EQ in some way. Adding more details and resonances increases the length and smoothing out decreases the length. An envelope would most likely just sound like an EQ tweak, but less predictable than using the already provided EQ.

Well, the length of an analyzed IR is preserved in MCabinet. So it makes as much sense to have an envelope at your disposal as in a real IR loader.
And as said, while the results might be less predictable, especially on IRs with plenty of ER content, the differences are almost like night and day, compared to plain EQing, at least once you play through such an IR (which is my main intention).

[Chandlerhimself]

MCabinet isn't really an IR loader, so this doesn't make much sense. Its actually closer to an EQ. When you import an IR it changes it into an EQ curve and then you can play with the curve in various ways. Trimming it or cutting is is equivalent to changing the EQ in some way. Adding more details and resonances increases the length and smoothing out decreases the length. An envelope would most likely just sound like an EQ tweak, but less predictable than using the already provided EQ.

Well, the length of an analyzed IR is preserved in MCabinet. So it makes as much sense to have an envelope at your disposal as in a real IR loader.
And as said, while the results might be less predictable, especially on IRs with plenty of ER content, the differences are almost like night and day, compared to plain EQing, at least once you play through such an IR (which is my main intention).

The length of the IR isn't preserved. When the IR converted it is changed,, but for short IRs this isn't really noticeable. If you load in an IR used for reverb you can clearly see it changes the length quite a bit.

If you want to get rid of resonances and ERs try using the smoothing parameters. If you look at the IR display you can see that the more you smooth it, not only does it get rid of the resonances you hear, but it also make the resulting IR(if you export it) shorter. Shortening the length is equivalent to smoothing the frequency response.

[Sascha Franck]

Well, with the cab/mic IRs I've thrown at MCabinet, the lenghths seemed to be preserved (but I'll be having another look into it later on). And I'm only talking about those.
I may as well have a look at the smoothing parameters again, but so far, nothing I was able to do in MCabinet got even close to the effect of trimming an IR with an envelope - otherwise I wouldn't even have started this thread.
And I don't agree on this:

Shortening the length is equivalent to smoothing the frequency response.

Frequency response doesn't have much to do with any time domain based processes. Shortening an IR does and you can literally feel the difference under your fingertips (or well, under your pick).

[Chandlerhimself]

Try using the smoothing yourself and see the difference in lengths. On average the IRs I import have a length of 90ms, but when I turn the Prof-smoothing all the way up they shorten to around 35ms. I'm pretty sure the EQ is effecting the time through the phase relationships of the various frequencies. Remember MCabinet isn't using the actual IR, its using an EQ profile of it, so somethings that make sense with IRs don't actually make sense with MCab.

[DarkStar]

Forgive my ignorance - could you clarify what an EQ profile of an IR is? Is that the same as the max curve generated when any audio sample is passed into an EQ? If not, what are the differences?

[imrae]

Frequency response doesn't have much to do with any time domain based processes.

Delays are (comb) filters, filters are (carefully tuned collections of) delays. And an IR is a very densely spaced series of delay taps.

[Chandlerhimself]

Forgive my ignorance - could you clarify what an EQ profile of an IR is? Is that the same as the max curve generated when any audio sample is passed into an EQ? If not, what are the differences?

Its similar to something like MFreeformEQ. Its like have a 100,000 band EQ and MCab finds the EQ setting that matches the IR. That EQ setting is the profile and from there you can manipulate it in various ways. I guess its technically the same as any EQ, but most EQs don't have the number of bands MCab does and the workflow is completely different. It also automates a bunch of things for you. There might be some other differences too, but the main thing is MCab is more like an EQ than an IR loader.

[DarkStar]

Understood, thank you.

[MeldaProduction]

Good points guys.

So sascha, as you can see, you would probably be the only one using it. I could add it of course, perhaps hide it somewhere, but without IR visualisation etc... And low priority.
Btw. MCabinet indeed does NOT preserve the length of the original IRs. And you are expected to analyze several IRs at once. If your IRs do preserve the length, it's likely because they are (close to) minimum phase already.