For all of you studio buffs out there: How many ambient mics do you use? Maybe a room and one in the back?
Not even that. If I'm recording more than one instrument (which is often the case) the bleed makes everything sound ambient enough. The rest of the time I'm generally more worried about removing ambience than adding it. Most rooms I record in are too small for the ambience to be terribly pleasant sounding, especially at the bottom end. My holy grail would be a room big enough that primary room modes are all sub-audio in frequency. That would be a much bigger live room than I can afford just now.
You'd think it would just be bass that's the problem, but unfortunately guitar amps do seem to excite sub-harmonics in the room when cranked up.
There are good reasons for keeping the recording in the virtual world. The real one is generally quite badly compromised. I do quite love the idea of these long IRs to simulate playing in a nicer sounding space than I am really in. But it's only going to work properly on headphones, or in a relatively dead sounding room at any reasonable SPL.
Liam