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How do i create impulse responses in Linux?

Posted: Wed Jan 22, 2014 9:56 pm
by Walnutcracker
I have a few amp modellers that i would like to capture the speaker cabinet emulations as impulse responses. What software under Linux could i use to create the impulse responses?

Re: How do i create impulse responses in Linux?

Posted: Fri Jan 24, 2014 8:01 pm
by ssj71
There's a program called qloud http://www.gaydenko.com/qloud/ I've used it. It will create an impulse response. Its fairly straightforward if you are familiar with IR work.
Another one is Aliki from Fons. http://kokkinizita.linuxaudio.org/linuxaudio/ Haven't used it, but if its from Fons, its good. :)

Guitarix may have something too but I'm not sure there.

Re: How do i create impulse responses in Linux?

Posted: Sat Jan 25, 2014 5:23 am
by tramp
ssj71 wrote:Guitarix may have something too but I'm not sure there.
Yes, guitarix have a tool called specmatch, which generate IR-files by spectral analysis.
http://guitarix.sourceforge.net/forum/v ... b4bd48fdb1

Re: How do i create impulse responses in Linux?

Posted: Sat Jan 25, 2014 11:25 am
by Walnutcracker
Thank you both for the recommendations. I will look into them :)

Re: How do i create impulse responses in Linux?

Posted: Sat Jan 25, 2014 3:51 pm
by funkmuscle
tramp wrote:
ssj71 wrote:Guitarix may have something too but I'm not sure there.
Yes, guitarix have a tool called specmatch, which generate IR-files by spectral analysis.
http://guitarix.sourceforge.net/forum/v ... b4bd48fdb1
hey tramp, specmatch makes really nice sounding IR for Guitarix but to use it with my hardware preamp it didn't sound good. Andreas and brummer said it's made to match Guitarix sounds only from what I remember. This is going back to when you first mentioned it. Has that changed?

Re: How do i create impulse responses in Linux?

Posted: Sat Jan 25, 2014 4:54 pm
by tramp
funkmuscle wrote:hey tramp, specmatch makes really nice sounding IR for Guitarix but to use it with my hardware preamp it didn't sound good. Andreas and brummer said it's made to match Guitarix sounds only from what I remember. This is going back to when you first mentioned it. Has that changed?
Don't know, but you have a command-line option --no-guitarix.
I guess it depend much on how you mic your amp (you must make sure that it don't clip), you must set the noise level, and the length for the IR-file, correct. As well, without using guitarix for pre-processing, you can only produce IR's for clean tones.
I've used it with and without guitarix, and I'm very suited with the resulting IR's. But indeed, special when use it with guitarix, it reminds me all the time on the kemper amp modeler.

Re: How do i create impulse responses in Linux?

Posted: Sat Jan 25, 2014 6:17 pm
by funkmuscle
tramp wrote:
funkmuscle wrote:hey tramp, specmatch makes really nice sounding IR for Guitarix but to use it with my hardware preamp it didn't sound good. Andreas and brummer said it's made to match Guitarix sounds only from what I remember. This is going back to when you first mentioned it. Has that changed?
Don't know, but you have a command-line option --no-guitarix.
I guess it depend much on how you mic your amp (you must make sure that it don't clip), you must set the noise level, and the length for the IR-file, correct. As well, without using guitarix for pre-processing, you can only produce IR's for clean tones.
I've used it with and without guitarix, and I'm very suited with the resulting IR's. But indeed, special when use it with guitarix, it reminds me all the time on the kemper amp modeler.

yeah it was the clean tones I was after. wasn't using a mic'd amp but a wav sample I found that I liked.

Re: How do i create impulse responses in Linux?

Posted: Sat Jan 25, 2014 8:00 pm
by tramp
funkmuscle wrote:yeah it was the clean tones I was after. wasn't using a mic'd amp but a wav sample I found that I liked.
Well, what should I say, I do the same, and it worked great for me. What did you use as reference file? Is hard to say what goes wrong with this less information. Maybe you must cut the file (set the range for the original file), maybe you must normalize it first (avoid clipping), maybe you must lower the gain of the reference file, maybe . . .
You could as well try the other mentioned options, but according to the user manuals, I guess aliki wouldn't work for this purpose, as it work with generated sweep signals, and is dedicated to generate room impulses.
http://kokkinizita.linuxaudio.org/linux ... manual.pdf
QLoud have the main purpose to measure a loudspeaker frequency, and use as well sweep signals.

Re: How do i create impulse responses in Linux?

Posted: Sat Jan 25, 2014 8:03 pm
by funkmuscle
tramp wrote:
funkmuscle wrote:yeah it was the clean tones I was after. wasn't using a mic'd amp but a wav sample I found that I liked.
Well, what should I say, I do the same, and it worked great for me. What did you use as reference file? Is hard to say what goes wrong with this less information. Maybe you must cut the file (set the range for the original file), maybe you must normalize it first (avoid clipping), maybe you must lower the gain of the reference file, maybe . . .
You could as well try the other mentioned options, but according to the user manuals, I guess aliki wouldn't work for this purpose, as it work with generated sweep signals, and is dedicated to generate room impulses.
http://kokkinizita.linuxaudio.org/linux ... manual.pdf
QLoud have the main purpose to measure a loudspeaker frequency, and use as well sweep signals.
most likely it was me screwing up. :mrgreen:

will try it again.

Re: How do i create impulse responses in Linux?

Posted: Mon Dec 01, 2014 3:29 pm
by DepreTux
Hi!

has anyone got specmatch running? When I launch it from console:

Code: Select all

$ specmatch --no-guitarix

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/specmatch/ui.py", line 632, in on_generate_ir
    self.calc.sound  # side-effect
  File "/usr/local/lib/python2.7/dist-packages/specmatch/spectrum.py", line 455, in sound
    rlen = len(self.a2)+len(self.ir)
  File "/usr/local/lib/python2.7/dist-packages/specmatch/spectrum.py", line 431, in ir
    self.ir_smoother = SmoothedIR(self.f1, self.f2, self.cutoff, self.rate)
  File "/usr/local/lib/python2.7/dist-packages/specmatch/spectrum.py", line 149, in __init__
    f = self.startslope(sqm, x, p)
  File "/usr/local/lib/python2.7/dist-packages/specmatch/spectrum.py", line 161, in startslope
    x1 = x[p+1]
IndexError: index out of bounds

Re: How do i create impulse responses in Linux?

Posted: Mon Dec 01, 2014 5:23 pm
by tramp
try a shorter sound snippet or select a part in the range around 00:10.0 from the "Original Sound"


note that the compare button wouldn’t show the result when the --no-guitarix option is set.
You can only check the plot in specmatch.
To check the result you need to deploy the ir-file and load it into your convolver of choice.

Re: How do i create impulse responses in Linux?

Posted: Mon Dec 01, 2014 11:30 pm
by DepreTux
actually the file i'm using is 0.8 seconds long.

The error comes up whenever I try to plot or generate an IR. The gui buttons get grayed, the status bar says "minimum phase filter".

I just realised that the terminal from which i launch X11 also spits an error message similar to the previous one that in the end says " runtime error, can't connect to guitarix".

Also, when I launch specmatch without the "no-guitarix" argument, guitarix launchs but says "failed to create avahi client: daemon not running." is the avahi daemon necessary for this?

Re: How do i create impulse responses in Linux?

Posted: Mon Dec 01, 2014 11:55 pm
by DepreTux
alright, I opened gutiarix first, then specmatch and now it goes through.

Is there a way to change the dark skin? It doesn't let me see which buttons are pressed.

Thanks!

Re: How do i create impulse responses in Linux?

Posted: Tue Dec 02, 2014 5:21 am
by tramp
DepreTux wrote:Is there a way to change the dark skin? It doesn't let me see which buttons are pressed.
Style is hard-coded, to change/remove it you need to edit the source.
file specmatch/ui.py line 412 <-> 447 define the style, line 107 (self.set_color()) set the style.
To use the system default style, just comment line 107 out (#self.set_color())
or edit the style in line 412 <-> 447 to your choice.

Re: How do i create impulse responses in Linux?

Posted: Tue Dec 02, 2014 6:39 pm
by tramp
DepreTux wrote:alright, I opened gutiarix first, then specmatch and now it goes through.
If it was the first time, you run guitarix, then it makes sense, as specmatch, use the guitarix configuration folder (~/.config/guitarix), to save it's own configuration (oh, surprise :) ), so, it at least indeed depend on guitarix, but, after that, it should run as well, without starting guitarix.
However, you could disable the guitarix amp in the tube menu, unload any effect, and use guitarix as a plain convolution engine, to make use of the compare button.