This vid seems to be showing some far better tones than the others... still don't understand IR though. http://www.youtube.com/watch?v=hnOqsSfaq80

See if the SONAR X1 Power book covers Perfect Space VST, it uses IR files.

I believe it does. In fact I think it is in the effects section I am currently working through. Cool.

I believe Guitar rig allows IRs too.

If Guitar Rig 4 or 5 has a way to add user IRs I have not found where.

My mistake. I must be thinking of something else. I have guitar rig 4, but I don't ever use it. Sorry for any confusion I may have caused.

Guitar Rig uses impulses (some of the best out there, by RedWirez, just like Scuffham), but I don't think you can load your own. 

Still, it's easy enough to bypass the cabinet emulation section of your amp sim and to simply place an IR loader like Perfect Space or, something  like my favorite impulses loader, MixIr2, by the same guys who did the RedWirez impulses. 

http://www.redwirez.com/mixir2.jsp

scook


If Guitar Rig 4 or 5 has a way to add user IRs I have not found where.

You have to have Reflektor (comes with Komplete)
http://www.native-instruments.com/#/en/products/producer/powered-by-guitar-rig/reflektor/
 
Here's an example:
http://www.youtube.com/watch?v=juAbnuscL6s
 

Impulse Response (IR) files are wav files of acoustic spaces eg a Hall, Theatre, Church etc. the list is unending.
They are typically used in Reverbs where the IR is used to simulate the reverb condition of the acoustic space.
So in practice if you wanted the reverb sound of a big auditorium you would look for an IR from a big auditorium. The wav files used are
Actually created in the space. So you might come across an IR from Madison Square Garden because that's where the IR was recorded.
Usually though the files are named in a more generic sense as per the usual reverb simulations large hall, small room, bathroom etc.

Thanks Rain for the pointer to MixIr2. Might have to pick it up on my next buying spree. I have played around with Perfect Space for cab IRs. Usually just use the cabs in GR, they are good enough for me.