KVR Audio

damstraversaz · Post by **damstraversaz** » Mon Dec 05, 2011 9:12 am

Hi
first sorry for my poor english.
i'm actually try a lot of thing with impulse reponse and reverberate core, and would like to know how to create impluse from 2 sounds. For exemple , I have a fx chain, and would like to manipulate this into reverberate, so I need to capture this signature.

thanks for reading
best,
damien

jupiter8 · Post by **jupiter8** » Mon Dec 05, 2011 9:47 am

Make an audio file where all samples are zero except one, that is fullscale. Play this thru the FX chain and record the result, That's your IR.

damstraversaz · Post by **damstraversaz** » Tue Dec 06, 2011 9:03 am

thanks, I will try this.

Damien

loopdon · Post by **loopdon** » Tue Dec 06, 2011 1:36 pm

I will, as well. Thanks for the explanation.

jupiter8 · Post by **jupiter8** » Tue Dec 06, 2011 1:40 pm

This works well for completely digital chains. For analog effects you most likely will need sinesweeps which is a bit more convoluted (no pun intended).

Voexengo has some stuff for that.
http://www.voxengo.com/product/deconvolver/

EDIT:If you're feeling adventorous you can experiment with recording some short burst of noise like a finger snap or handclap in any room and use that. IR files are just regular audio files.

magicmusic · Post by **magicmusic** » Wed Jul 23, 2014 12:11 pm

I want record a guitar speaker with sound i like. I see there are sine sweep files

http://www.audioease.com/Pages/Altiverb/sampling.php

does somebody know a free of cost way to create from such sine sweeps the impulse response ?
I guess the original sine sweep data need subtract from the original data. so i hope a simple free or opensource program can do it.

JCJR · Post by **JCJR** » Wed Jul 23, 2014 10:10 pm

There is a (very good) free room analysis software Room EQ Wizard. Googlable. It outputs sine sweeps and records from a measurement mic (attached to your puter input) to analyze room acoustics.

I have never tried REW for your purpose, but one of the many things it will do is deconvolve the sine sweep it recorded and display/save the derived impulse response file.

I see no reason that REW would not be able to generate an impulse response from your guitar speaker, but dunno.

Am guessing it would also be interesting to place the guitar speaker in special miked situations, in live rooms, specific mic and location, and capture the whole shebang in one go. Everything in a single composite impulse response.

If you want the "naked" speaker response only, and do not have access to an anechoic chamber, possibly use a measurement mic or the flattest condenser mic you have, set the speaker up on a chair or sawhorses outdoors with no objects or buildings near the speaker.

The impulse response process is linear-- An impulse response unfortunately can't capture the nonlinear properties of the speaker such as its behavior under overload distortion.

magicmusic · Post by **magicmusic** » Fri Jul 25, 2014 4:24 pm

is there another program that need no Java ?
thanks, this allow the save of impulse responses in Mono only, say the documentation. but is ok to test if it sound ok. I try both my AV receiver measure microphone or Zoom H1.

Only i dislike is that it need Java. I have not install it to reduce risc of Virus. currently i not need, but if there is no simular free program i try.

JCJR · Post by **JCJR** » Fri Jul 25, 2014 5:49 pm

Re java I'm no expert but the first rule I follow is to avoid surfing with any computer which contains sensitive information. That way there is nothing of consequence to get lost or stolen.

Also you can disable use of java in your browser even if installed in your system, though it is rather tortuous to surf the web without at least javascript enabled (which supposedly might have fewer security risks).

Lastly, java does release routine security updates, and everything computer related has security holes, some so obscure that possibly not every single one of them will ever be discovered.

The preferred way to use REW, and the best success I had using asio, the analysis mic goes to one input channel and the output sine sweep is looped back to the other input channel. That way, the sotware has a built-in timing reference between source and result, avoiding any soundcard latency mistakes which could confuse the measurement.

For a stereo impulse file, if sampling a stereo source from a single location, you could for instance turn off the right speaker and do a sweep of the left speaker room response, then turn off the left speaker and do a sweep of the right speaker room response, giving two IR's which could be merged to stereo in an audio editor program.

If instead you wish a stereo IR with different mic types, locations or aiming, just do one IR with the first mic config, then a second IR using the second mic config. Leave the source the same for both sweeps, but move or change the mics between sweeps.

I have never done either of those for stereo IR, but "it ought to work".

The way REW records a loopback reference for each sweep, sync ought to be very good between sweeps taken at different times and different conditions.

For room analysis or room reverb IR files, a flat omni mic would be desired, but for instance to capture a celestion greenback miked with a sm57, or an ampeg fliptop miked with an RE20, using the non-flat mic at desired location "ought to" capture the entire speaker/mic/room interaction in one fell swoop.

how to create impulse reponse from a dry and wet sound ?