# Adding modulation to Impulse Responses?



## SomeGuy (Jan 12, 2019)

I have a few IR's of high quality analog gear, but the issue is these IR's are like static pictures, where their analog equivalents are moving and modulating. Is there any convolution software where you can add back in the modulations to help make convolution IR's sound more "alive?"


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## bengoss (Jan 12, 2019)

SomeGuy said:


> I have a few IR's of high quality analog gear, but the issue is these IR's are like static pictures, where their analog equivalents are moving and modulating. Is there any convolution software where you can add back in the modulations to help make convolution IR's sound more "alive?"


Finially someone!
I’ve been trying all sorts of things in the past couple of months with Altiverb.
And yes you are totally right. Most of the IRs are super static and you get the same timbre no matter what’s the amplitude of the sound. I tried playing with decay time and got some nice results. Ill post some audio samples soon.


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## clisma (Jan 12, 2019)

SomeGuy said:


> I have a few IR's of high quality analog gear, but the issue is these IR's are like static pictures, where their analog equivalents are moving and modulating. Is there any convolution software where you can add back in the modulations to help make convolution IR's sound more "alive?"


If you’re talking about reverb IRs, you could try Reverberate. It features deep control over the IRs, including modulation. I’m currently trying it out with some microphone IRs.

https://www.liquidsonics.com/software/reverberate-2/


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## SomeGuy (Jan 14, 2019)

bengoss said:


> Finially someone!
> I’ve been trying all sorts of things in the past couple of months with Altiverb.
> And yes you are totally right. Most of the IRs are super static and you get the same timbre no matter what’s the amplitude of the sound. I tried playing with decay time and got some nice results. Ill post some audio samples soon.



This is exactly right! Would love to hear your solution when you are able.


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## SomeGuy (Jan 14, 2019)

clisma said:


> If you’re talking about reverb IRs, you could try Reverberate. It features deep control over the IRs, including modulation. I’m currently trying it out with some microphone IRs.
> 
> https://www.liquidsonics.com/software/reverberate-2/



Thanks, will check this out! Does the modulation only work to blend between two different IR or can it modulate other aspects of the sound? Will of course demo myself as well.


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## averystemmler (Jan 14, 2019)

SomeGuy said:


> Thanks, will check this out! Does the modulation only work to blend between two different IR or can it modulate other aspects of the sound? Will of course demo myself as well.



Reverberate has some interesting options. There are two IR slots that can be modulated between, but there is also the notion of "fusion IRs," which are single IRs containing multiple variations that modulate within themselves, kinda like a multisampled impulse. You can put one of these in each IR slot, and modulate between them.

Then, each IR has a chorus, delay, and EQ. The EQ can be set to change over the length of each impulse, which can create a dampening effect like you'd find in an algorithmic reverb. The chorus is post IR, but there's a "splitmod" for each slot as well which can modulate pitch for the ER and tail sections independently.

You can have each IR and its chain in series or parallel, followed by additional master chorus, delay, and EQ modules at the end of the chain.

Each IR also has start position, length, ADSHR, width, predelay, pan, and gain controls, the combination of which allow you to do some pretty tremendous shaping.

And, finally, you can also opt to put an algorithmic ER or tail generator in either of the slots instead, with a decent assortment of parameters to fiddle with.

If nothing else, they give you choices!


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## Henu (Jan 14, 2019)

You can also slap a modulation plugin as an insert after your reverb and use a very slight mix setting. Granted, it's not the same thing but you can get some really cool results doing that.

...or just get a Lexicon/ equivalent-sounding plugin and call it a day. 

EDIT: Now I got myself really interested on Reverberate- curse you @averystemmler ! :D


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## averystemmler (Jan 14, 2019)

Henu said:


> EDIT: Now I got myself really interested on Reverberate- curse you @averystemmler ! :



If this helps your decision at all: liquidsonics gives some nice loyalty discounts on each of their plugins to owners of the others.


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## Living Fossil (Jan 14, 2019)

Henu said:


> You can also slap a modulation plugin as an insert after your reverb and use a very slight mix setting.



I'd rather put the modulation plug in _before_ the reverb.


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## Henu (Jan 14, 2019)

I'm talking about reverb sends- you seemingly aren't? Or do I misunderstand something now?


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## fixxer49 (Jan 14, 2019)

Henu said:


> You can also slap a modulation plugin as an insert after your reverb and use a very slight mix setting. Granted, it's not the same thing but you can get some really cool results doing that.


+1. This.
The old Acoustica impulses actually came packaged with presets for the Mod Delay plugin in Pro Tools.


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## robgb (Jan 14, 2019)




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## averystemmler (Jan 14, 2019)

Henu said:


> I'm talking about reverb sends- you seemingly aren't? Or do I misunderstand something now?


I don't want to put words in his mouth, but generally speaking, I find I get much more natural results when affecting a send pre-reverb than post. It's the difference between applying vibrato to the flute and apply vibrato to the hall (to use a dumb analogy).

Which is to say, I'd put modulation in the effect slot before the reverb, but still on the send.


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## Living Fossil (Jan 14, 2019)

Henu said:


> I'm talking about reverb sends- you seemingly aren't?



Of course i do 

On your bus you put the chorus (or whatever kind of modulation) _before_ your reverb.
This way, the modulated signal gets reverberated.
Which results in a denser reverb.


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## Henu (Jan 14, 2019)

Wow, I've actually never heard about that nor have I thought about it before!

When I think of modulating reverb, my first impression would be the slightly modulated and living tail, and to be honest I still cannot comprehend completely this idea...but I've gotta try it out, haha! Thanks for the tip, one lives and learns! ^^


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## Living Fossil (Jan 14, 2019)

Henu said:


> When I think of modulating reverb, my first impression would be the slightly modulated and living tail, and to be honest I still cannot comprehend completely this idea...but I've gotta try it out, haha! Thanks for the tip, one lives and learns! ^^





Funny thing is, i also thought that i have to try out it the way you described it.


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## averystemmler (Jan 14, 2019)

Henu said:


> Wow, I've actually never heard about that nor have I thought about it before!
> 
> When I think of modulating reverb, my first impression would be the slightly modulated and living tail, and to be honest I still cannot comprehend completely this idea...but I've gotta try it out, haha! Thanks for the tip, one lives and learns! ^^



In some reverbs, that modulated and living tail is actually created by applying the modulation to the dry signal internally, before it hits the "reverb" part. You might be doing this already without realizing it.

A large part of the advantage of this is that it helps to prevent resonances from forming. Since reverbs are really just delays (upon delays upon delays upon delays... diffused with allpass filters and psychoacoustic magic that I don't claim to understand), multiple identical signals offset slightly in time will phase and ring and generally make a mess. 

So changing the input signal over time is a simple way to keep those resonances from forming, since each delay tap is echoing a slightly different version of the signal.

Putting the modulation after can have a cool effect too, but it'll just be wiggling the already formed resonance around. But since a lot of plugins deal with this internally already (and maybe impulse responses are less relevant here, since they already contain some of the natural imperfections and diffusion of a real space?), my reasoning for putting modulation pre-verb would be more for the aesthetic effect it has, blurring the wobbles together.


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## Divico (Jan 14, 2019)

robgb said:


>



Nice one. on its own it sounds bad but in context it makes the verb more credible. At least for me


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## Beat Kaufmann (Jan 15, 2019)

HOFA IQ-Reverb


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## Chandler (Jan 16, 2019)

Melda’s MconvolutionMB allows you to add modulation before the IR. It also allows you to modulate between different IRs if that’s what you want. 

Adding a little modulation before an IR can really add a bit of life to the sound. If you do too much it will sound like chorusing though.


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## aaronventure (Jan 24, 2019)

Living Fossil said:


> Of course i do
> 
> On your bus you put the chorus (or whatever kind of modulation) _before_ your reverb.
> This way, the modulated signal gets reverberated.
> Which results in a denser reverb.


The result is a sound that seems "modulated", until you stop the dry signal and you hear the tail alone (also when you notice the reverb the most) and it remains static, which kinda defeats the purpose of modulation IMO.


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## Living Fossil (Jan 24, 2019)

aaronventure said:


> The result is a sound that seems "modulated", until you stop the dry signal and you hear the tail alone (also when you notice the reverb the most) and it remains static, which kinda defeats the purpose of modulation IMO.



In 99.7% of the cases i hate it, when i actively hear an ongoing modulation in an isolated reverb tail. 
So, what you describe as negative for you, would be positive for me.
Honestly, it even would qualify as a feature request for algorithmic reverbs that the modulation stops, once the signal stops.


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## aaronventure (Jan 24, 2019)

Living Fossil said:


> In 99.7% of the cases i hate it, when i actively hear an ongoing modulation in an isolated reverb tail.
> So, what you describe as negative for you, would be positive for me.
> Honestly, it even would qualify as a feature request for algorithmic reverbs that the modulation stops, once the signal stops.


Well if that's your preference, alright.

If a reverb has a built in modulation amount knob (and it doesn't experience a seizure if you're moving it while it's outputting audio), you can sidechain it to to the actual dry signal (given that your DAW has this feature).

In Reaper, you would send the dry signal to additional channels on the track, then click on the amount knob (or any other control you wish to sidechain), click on Parameter modulation, select the tracks that you duplicated the signal to and dial in your threshold, attack, release, etc. So you set it up so that when there's no dry signal, modulation goes away. And you can set the attack and release in such a way that it's either a drastic change, or a more transparent one.


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## Living Fossil (Jan 24, 2019)

It's easier to choose the right reverb in the first place...


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## Dietz (Jan 24, 2019)

Living Fossil said:


> I'd rather put the modulation plug in _before_ the reverb.


Exactly. I use IR-based reverb very often that way, with an unobtrusive ensemble/chorus-effect on the dry aux-send before it enters the convolution engine. Works on pretty much every tuned musical signal, ideally on polyphonic instruments or ensembles. Not so great on (untuned) percussion, though. 

... best approach is to have slightly different modulators for different (groups of) sources.


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## Ike_Co (Oct 3, 2021)

Interesting thread. I'm a huge convolution fan, but I agree that it can sound a bit static. 

Since you are talking about modulating the reverb tail: are you thinking primarily of chorus / ensemble type of signal modulation or what type of modulation would be suitable here?

Also, what do you think about this approach:

two aux / send busses / return channels (send fx channels, whatever they are called in your DAW). 1. with an impulse response of early reflections only. Fully wet. 2nd one with a modulation plugin first set to reasonable values (no extreme modulation, just some slight movement) followed by a convolution of reverb tail only, fully wet. Could be a chamber, room, hall, plate tail - whatver is suitable for your material. This "modulated tail" part could also be done with an algo reverb of course. This way you can independently control the amount of ER and modulated tail both running in parallel. Sure, there are a few sophisticated convolution reverbs already doing this, Liquidsonics fantastic stuff in particular, but with this approach you can use any reverb in your arsenal. 

Sometimes sending material with slight impulse reverb (eg 20% wet) into another fully wet impulse response can yield interesting results. Works particularly well with spring reverb, if you are going into feedbacky-psychedelic territory.


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