# What method and software are you using to make your own IRs?



## UCAudio (Aug 1, 2011)

I have some gear that I want to make impulse responses out of... old spring reverbs etc... and also some nice acoustic spaces. What is the best software for doing that? I looked a while back and wasn't really able to find a good solution.


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## polypx (Aug 2, 2011)

Try Voxengo's Deconvolver. Works very well. http://www.voxengo.com/product/deconvolver/

cheers
Dan


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## ScoringFilm (Aug 2, 2011)

I have tried both the sweep and spike methods and can vouch 100% for the spike method; creates consistent results every time and no deconvolution needed:

1) Place the "spike" audio on an audio track in any sequencer/audio editor

2) Set-up a digital-reverb on a buss (set to 100% wet) - use spdif etc for hardware.

3) Route the "spike" output to the Reverb buss. 

4) Bounce/record in real-time the reverberated spike only (i.e. no direct signal just the buss output). It may take a few attempts to get the right levels and the result is your IR.

5) Open the IR in a sample-editor and chop the the front and rear. You can also add pre-delay (i.e. silence) to your taste to save on CPU processing in your convolution software.

DONE!

You can also setup true stereo, 5.1 etc with more busses or pan to get L/C/R IRs.


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## UCAudio (Aug 3, 2011)

Interesting, the deconvolver looks great but I'm not sure if it is windows only as I'm using a mac. That spike method is really interesting as well considering I don't need any special software. 

I used to think that method wouldn't work as good as the sweep method... thinking the sweep method could be swept slowly to more accurately capture the response at ever frequency... but in you're experience that is not the case?

How would you change the steps you listed if you were attempting to create a true stereo IR?


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## ScoringFilm (Aug 3, 2011)

What I suggest is that you try both methods and compare the results. For true stereo you would need to route the outputs/busses appropriately and then create separate L & R responses.

Justin


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## polypx (Aug 3, 2011)

The spike method works great for software or some hardware outboard... you need to get enough level to move the unit you're trying to capture.

A single sample spike doesn't contain enough energy to get some devices moving though... ie. a concert hall... in which case a sine sweep is needed.

In my experience, sine sweeps have usually been more even spectrally than a spike or "gunshot" IR. But both can work well depending on the situation.

cheers
Dan


PS I run Windows on my Mac (VMWare) pretty much solely for Voxengo's deconvolver.


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## UCAudio (Aug 4, 2011)

Alright cool, thanks for all of the info. I've never tried running any windows software on OSX... that's great to know that it is possible.

Quick question for you guys. So if I send a sound through my old Space Echo spring verb... and it's a loud sound... the response is different... more distorted and the spring bangs around. If I send a quieter sound through it it is smoother. 

Is there such a thing as dynamic IR where you record your tone through your reverb at different volume levels so that the IR based reverb plugin (or Kontakt in this case) will respond in a more realistic way based on the volume level of your source material?


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## polypx (Aug 4, 2011)

There's no "dynamic IR" in Kontakt. You could theoretically script something like that but it would be stepped, and you'd have only 6 convolution steps.

Dynamic IR is something to look forward to. I think this is something really interesting for the future. But I don't have any tools to do that with yet.


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## TuwaSni (Aug 6, 2011)

Just curious - what type of IRs are you trying to generate? Spatial/reverblike? FX (pans/smears/etc.)? Convolution synthesis? Different methods and sources for each.

TS


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## UCAudio (Aug 7, 2011)

Initially I want to create IRs of some old analog spring reverbs... some gritty vintage digital verbs... as well as some acoustic spaces.


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## TuwaSni (Aug 7, 2011)

UCAudio @ Sun Aug 07 said:


> Initially I want to create IRs of some old analog spring reverbs... some gritty vintage digital verbs... as well as some acoustic spaces.



For IRing strictly reverb/spatial stuff - then I agree with the previous spike/sweep discussions. If you are targeting percussive material then the spike/pink noise approach tends to produce better results - if targeting more pitched/longer duration oriented stuff then sweeps tend to produce better results.

For acoustic spaces - noise bursting is easier as you don't have to create a frequency correcting scheme to account for your playback system's response if you use a sweep
method. Be sure to use pink noise and not white noise. (But that being said - if you have the tools to do the frequency corrective stuff then a sweep method will produce better results.)

TS


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