Non-reverb convolution (tone/amp simulation)?

    Apr 01 2012 | 1:21 am
    Did a search but didn't turn anything up.
    Has anyone run into tone-based convolution (rather than reverb/space based stuff)?
    I want to add some simple (in terms of control) amp simulation to one of my patches, so that it sounds like a clean channel on a guitar amp, but coming out of a PA/full-range system.
    I'm thinking that using convolution would be better sounding, and simpler to build, rather than trying to model and chain together all the elements that would make an amp sound like an amp.
    I've seen some plugins that use that approach (primarily 'colortone pro'), but haven't seen any patches on the forum for that kind of thing. Also not sure how to go about making an IR for something like that either (though I suppose there are IRs a plenty out there).

    • Apr 01 2012 | 1:41 am
      afaik the tech is identical, ie extract an impulse response from the unit/space and then convolve. "Impulse response" means system reaction to signal of theoretically infinite amplitude and frequency spectrum and theoretically zero time. In the old days I am told they used starter pistols. System can be any piece of hardware or any physical space.
      Can I say for certain that that's what they do in that plugin? No. But if it isn't their use of the word convolution is misguided.
    • Apr 01 2012 | 1:56 am
      That's what I figured, I've just not run into patches that use convolution that way. Nearly everything has been either reverb-based, or at least has a time/blur sound to it.
      With a non-time based system (like the passive tone of a guitar amplifier) I'm not sure how an attack-based impulse would get any information since it would be as long as sound created (whereas in a church, the tail is much longer than the impulse), though honestly I'm not up on the specifics of how IRs are made either way.
      A quick google looks like sine sweeps are handy for amp IRs.
    • Apr 01 2012 | 2:00 am
      Not true. Adding harmonics alters signal in both frequency and time domain.
    • Apr 01 2012 | 2:10 am
      Found these online. Haven't tested them out yet.
    • Apr 01 2012 | 2:15 am
      Excellent, will play later
      Iirc voxengo perfect space, that ships/shipped with sonar, included some cabs
    • Apr 01 2012 | 2:22 am
      I'll take a look, but I want to use more than just a cab sound, and have the preamp/amp sound involved too.
      After a quick poke those amp IRs I linked sound pretty good
    • Apr 01 2012 | 2:28 am
      Well, yea that,s what I meant.
    • Apr 01 2012 | 1:07 pm
      Rodrigo - have you tried Alex Harker's convolution patches - they are really great and should work for what you want. Make an Impulse Response of your amp with a test sweep /deconvolve it and then use it the exact same way as a reverb IR. In convolution, reverb can be thought of as a kind of filter. I used Alex Harker's patches to make a talking sword and singing wind - the IR does not have to be reverb it can be any sample at all. Voxengo have a free deconvolver (windows only) and if you have SoundForge you can download test tones from their website and use the Acoustic Mirror to deconvolve. I am not sure if there is a deconvolver in Alex Harkers suite - I just ripped the zero-latency reverb patch (for which I am extremely grateful) and made it into an M4L device and did not do much more than that yet. Maybe others may know more about the deconvolution process using Alex's externals.
    • Apr 01 2012 | 1:26 pm
      Yeah that's what I'm using (his zero-latency abstraction and objects).
      I just hadn't used them this way yet. I ended up using a few IRs from that link I posted up there.
      In that plugin I mentioned earlier (Colortone Pro) (which was originally built in max/pluggo) there's a control to increase/decrease the amount of convolution applied. I don't think it's a blend control as you can go more than 100%, in terms of how much convolution to apply.