Impulses

[michaelt523]

I feel like i've been living under a rock....in a cave....on mars.

There are numerous submissions in the metal guitar wars that utilize impulses, can someone explain just what these are and what they do?

[richiebee]

Convolution uses several types of noise signal to record a particular space, whether it be a room, concert hall or guitar cabinet. When the noise is removed, all that's left is what that space sounds like. At least, that's the basic theory.

It's most common use is to create a reverb that is very realistic to the space it represents, by recording the impulse in that space. I've tried it myself, and the practical is a little more complicated.

This might help a little better than I can... Convolution reverb - Wikipedia, the free encyclopedia

[tacman7]

There is also use of impulses in guitar modeling.

[richiebee]

But its the same thing though right? Recording a test tone through an amp or stomp or whatever, and then removing the test tone to leave what that device sounds like.

[Metaltyme]

But its the same thing though right? Recording a test tone through an amp or stomp or whatever, and then removing the test tone to leave what that device sounds like.

Yes...that's correct as far as I understand it.

[tacman7]

In the guitar stuff, seems like you could use any wav file (really short) as a basis for distortion, then there were impulses to model speaker cabs.

I was looking into this stuff sometime back but it was more than I wanted to get into, I have too much crap for guitar already.

Quick search:
NEW Speaker Cabinet Impulse Response Library - Guaranteed to Grow More Hair - Gearslutz.com

Guitar Cab Impulse Files - Page 2 - Home Recording

Guitar Amp Modeling • View topic - How to use impulses

[garww]

I would call it a mask

[bozmillar]

basically, if you convolve with an impulse response, it sounds like it would if you were playing the sound through whatever room or filter or speaker that the impulse response came from.

You can only model linear systems with an impulse response.

[bozmillar]

You can't use an impulse to model distortion, because distortion is non-linear. You can use it to model the frequency and phase response of a speaker, but again, not any of the non-linear aspects of it.

[brandondrury]

You can only model linear systems with an impulse response.

Just to explain it a little simpler.....

If you have an amp set for medium gain and you REALLY dig in, it'll be all distorted. If you play super lightly, it'll clean way up. At this point in time, impulses don't take dynamics into account.

Brandon

[michaelt523]

Thanks for the responses. This is some pretty advanced stuff, i'm glad to have at least a basic understanding now.