For the record (or people not knowing, reading from the thread):
RIR2 can't work with any random impulse out there, so you can't use it for your custom impulses.
The most (or only) important new part of RIR2 is the capturing of the interaction between amp and a cabinet. This is the 'extra' stuff they captured with RIR2, and is why you can't just load any random impulse in it.
This interaction thing only works with the Revalver amps, since they only supply the data that RIR2 needs to do the impedance-changes.
So putting X50 (with cab off) into RIR2 won't do anything special in RIR2.
So it's a bit of a shame, but (IMHO) the most important new thing only works when you use RIR2.. and for me it takes a lot of getting used to using somebody else's IR captures again :S.
Revalver always had the tendency to be light on bass-output and become 'boxy' or 'too mid-present' very quickly. The new 6505(+) seems to have fixed that somewhat (with using an external 808 plugin and using NadIR for impulse loading, X50v2 and Rv4 come really really close with using the knobs on the same settings. X50's input level trim is way higher by default (the reason for the higher gain if you don't change it)... input level needs to be matched with every amp sim people, they're almost never the same).
The Flathill (recto) still seems to have a lot of it though. For instance, comparing the same knob positions with the same DI + 808 + IR, I rendered Lecto (with resonance at 0), Th2 and StudioDevil's A.M.P. and then Revalver4. The first 2 are close... _scary_ close. The 3rd is also close, but is just a bit less on bass.. a bit, still sounds full.. The 4th (Revalver) suddenly sounds like all the bass is gone and very boxy. Increasing the treble and presence _a bit_, dropping the mids _a bit_ but throwing the bass from 4 to 9 got Revalver _very_ close. But it needed the bass knob to be on a complete other position.
So it can do the same, and sound just as good, but something in the modeling (or the model they did) is off compared to 'the other sims' out there
. Or the tonestack is completely different.
Did the same with Amplitube, and it also sounded close but way darker. Since it didn't have a presence control this is kinda expected.
Try as I might I can't get the exact same tone out of Guitar Rig. I always felt something was 'wrong' with the way the knobs responded. Turning the mids low added a nasty 'hssssss' to everything, and no matter how high I turn the treble or presence, it seems very dark and boxy compared to the others.
So Revalver4 certainly seems to got the tone, just set the tonestack by ear and not with your eyes (which makes sense and isn't a bad thing).. and remember that RIR2 can only add something when paired with a Revalver4 amp (there seem to be bugs when using multiple amps and chain-splitters, RIR2 doesn't know to 'link' to which amp when doing the speaker-interaction thing
).