Capturing Impulses...software, techniques.

[Lindon]

@lalalandsynth ok well I'm very slightly less envious then...

[lalalandsynth]

Must collect them all!

[lalalandsynth]

So am capturing the EMT 244 today . it does have quite a bit of low end hums and noise , any thoughts on how to deal with that kind of thing , as it is the noise would be added to the impulse.

[tomekslesicki]

@lalalandsynth That's a super-nice studio! Regarding the noise from the EMT - you might want to capture a bit of that after the sweep and noise reduce the impulse in RX.

And when it comes to mics, this might be of interest to you: http://micirp.blogspot.com/p/about-micirp.html :-)

[lalalandsynth]

Looks like i am getting some aliasing ?
I should have tested a longer impulse to see if there was less aliasing , just to be sure , dont know if that would change anything ? Having said that , if aliasing is part of the sound then so be it :)

This impulse is from the EMT 246 which really only goes to 12k (probably contributes to how nice it sounds) and the "aliasing" is pretty clear.

Also wondering if I should normalize impulses before deconvolving or if I should normalize the resulting impulse , guess I need to do some tests.

[lalalandsynth]

Couple of questions .

1. What is the max length of an impulse in the convolution Reberb ?

2. I know "UseBackgroundThread if true , then the convolution will be executed on a background thread." but what does that mean in practice ?

3. is it possible somehow to set the gain pre impulse ? Pre-preset .
   So not on the convolution reverb gui but maybe via some sort of scripting ?

4. When using a Tick/sample to make an impulse of a static setting , after deconvolving it just sounds like a phase mess when mixed with the dry signal, what are the techniques to get this right ...I guess I would need to measure the recording latency ?

Suggestion , it would be nice to have a setting that could offset the start of the impulse. to remove predelay if needed , rather then having to edit the predelay out of the impulse.

[lalalandsynth]

Ok, after editing impulses all day I am having thoughts about levels and normalizing.

After looking at impulses from waves IR-1 for example , they are all normalized and quite a few of them clip when set to 100% wet.

I also noticed then when my sweep file is peaking at -3 dB and then I deconvolve , the resulting impulse is at -29db.
I am assuming this is normal after deconvolving but it means I definitely need to normalize.
Using the impulse untouched in an impulse reverb and it way too low.

I guess normalize and then set all impulses to -3 to -6 ?

[lalalandsynth]

Does anyone have experience of taking "static" impulses , like speakers , eq's etc ?

I did try a couple of those but had massive phase issues when blending with dry signal.
What procedure should one use to capture the impulse and maintain phase coherence ?

[hisefilo]

this is what I'm using, if it helps.

[lalalandsynth]

Are you using this for a static impulse, rather then reverb and such ?

[hisefilo]

@lalalandsynth I just opened and last thing I did remains there. It's a reverb impulse if remember correctly (a test in my room)

[Natan]

@lalalandsynth said in Capturing Impulses...software, techniques.:

What is the max length of an impulse in the convolution Reberb ?

Did anyone get an Answer For This?
@Christoph-Hart

[Christoph Hart]

There's no artificial limit (it throws an assertion for impulses > 20 seconds, but that's just in debug mode), so the limit is your CPU.