The great clip project

[m0jo]

We hear/make complaints often here that it's hard to compare different modules, especially from modders as they can't be easily demo'd (or not at all).

So I had this idea:
Why not choose an IR and a DI'd guitar track (or some different ones for extra balance).
Then everyone who has the tools (a passive DI and a reasonable audio interface) can contribute to creating a database of clips of all existing modules, stock and modded!

To help out, all you'd have to do is reamp the DI track through the amp, record the FX send (or RM4 output) and put it throught the IR.
That way all the "guitars" and "speakers and mics" are equal and the pure difference is the module and maybe the V1 tube in the amp .. a small detail compared to the rest.

What do you guys think of this idea?

 

[m0jo]

A sidenote on this:
Of course you will miss the interaction with the amps and such, so it won't be an exact image of the tone, but I think it would be more than good enough to make choices regarding to which one will work for you.

 

[Jaded Faith]

So maybe I am a little old school still miking up speakers or just behind the times a little, but can you fill me in on these IR's I hear you guys talking about? A little application info, background and any suggested ones would be a good start.

 

[iekobrid]

The 'short' answer is:

Programs called "convolution reverbs" were developed to help computers model the acoustic properties of physical spaces. The basic idea was that if you put a speaker at one end of a room, use it to play a prerecorded sound, and re-record it through a mic at the other end of the room, software can then compare the original sound to the re-recorded sound and compute how passing through that space altered it. An "impulse response" or IR file is created, which can be loaded into a convolution reverb program to make any recording you like sound like it passed through that specific physical space.

Eventually someone realized that each impulse was not only a snapshot of the acoustic properties of a physical space, but also of the signal chain involved in creating the IR. For example, using a ribbon microphone to capture a sound being played through a solid state power amp into a 1x8 speaker in an open back cabinet is going to result in a significantly different IR file than the exact same wave being played through a tube power amp into a 4x12 closed back cabinet mic'd with a Shure 57.

Audio engineers (pro and hobbyist alike) took advantage of that fact and created their own impulse responses so they could record the preamp signal of a real guitar head and run it into their studio computer, where the rest of the signal chain is simulated by a convolution program running whichever IR file they deem most appropriate for the song. Think it sounds best with a Marshall 4x12 and a Shure mic 2" from the speaker cone? Call up IR #22. Want to try it with a Vox 2x12 and a Royer a foot away? Pull up IR # 38 instead. No need to go back and re-record the whole track just to get a different guitar tone or wake your neighbors with window rattling stacks.

The makers of products like Recabinet take a cabinet and create dozens if not hundreds of IR files of it with every microphone and mic position combination they can think of, then package them into a proprietary interface that allows the end user to easily switch between options and make adjustments.

 

[m0jo]

Yep, so basically it's a very good emulation of the poweramp, cab, speakers, room and mic.
This also means people like me can create far better recordings from their bedroom, all my recordings are done with IR's.

There are also people who offer them for free like GuitarHack, these are actually better then a lot of "pro" ones.

This is the one I use, I mixed some different (free) ones together to make a perfect tone for me, just like you would mix recordings from multiple cabs and mics.
http://dl.dropbox.com/u/7181889/m0jo%20-%20Custom%20IR1.wav

Now you probably understand why I mentioned this as part of the idea: basically the entire signal chain around the preamp will be a static, the only variables being the module and actual variances in the preamps. That is the closest we can get to a fair comparison without AB'ing in real life Maybe even more so because there's no variables in your playing.

EDIT:
A little side info: a lot of newer pro-modelers use IRs for their cabinet models.
Axe-FX, Eleven Rack, GSP1101.

 

[Jaded Faith]

Excellent explanations gents. I came to MTS from in 2007 after 5 years with a Line 6 Vetta, so this sounds like a improved PC based version of the cab/mic sims back in that rig. I can imagine the quality has improved over this past decade and I certainly see the perks it can offer.

So aside from Recabinet, are there any other highly recommended products?

Mojo: That link is a 2 second audio wave with one audible pop in it. Is that what it was supposed to be?

 

[m0jo]

Excellent explanations gents. I came to MTS from in 2007 after 5 years with a Line 6 Vetta, so this sounds like a improved PC based version of the cab/mic sims back in that rig. I can imagine the quality has improved over this past decade and I certainly see the perks it can offer.

So aside from Recabinet, are there any other highly recommended products?

Mojo: That link is a 2 second audio wave with one audible pop in it. Is that what it was supposed to be?

Yes there has been some improvement in the quality, but it also depends on who makes them. It is an exact measurement of the tone created, including the mic(s), so if you're not good at micing a cab, your impulses will not sound good either.
The standard GSP1101 impulses are pretty crappy IMO, loading custom ones in made it worthwile for me.
As for producers, there's Red Wires and the GuitarHack impulses are pretty good.

Yes, that clip is an impulse response!!
What happens with creating it like iekobrid says, is that an impulse (pop) is played through the rig and recorded, this file is the outcome of that.

You can load this into a plugin like ReaVerb, KeFIR or Boogex.
Then just plug in your preamp and rock out

 

[Julia]

Note: with some programs like Altiverb, Waves IR1 you can make your own IRs. Otherwise you can load the premade ones, which is what i use. Redwirez has a list of loaders on their page. If you have Pro Tools you will need RTAS which will limit you to one of the not free ones. Mellowmuse is only mono and 16 bit 44.1 kHz, but is $50. IR1 is $180 but you get a huge library with it and there's a lot of tweaks you can apply. Altiverb is $600 and I didn't even look at it.