obviously,a tube amp and shure57 will give the most authentic warm sound possible. but----and this is the BIG but...when the track is mixed along with bass,drums,vocals and maybe a synth AND processed with several effects including compressors etc. ---- who on earth will be able to tell wheather i recorded my guitar direct via a POD X3 or via a MARSHALL and a set of pedals.
d'you get the idea??...
now show me where am i mistaken here.
Something tells me you don't think you ARE mistaken here (I'm hearing that Tucker Someone-or-other-who-thinks-bow-ties-are-still-in from CNN's Crossfire), but all the same I'll take the bait.
I think you're missing one fairly crucial point. Your argument seems to be, if I may paraphrase, that "given all the other instruments going on in a mix, any quality difference between an amp modeler and a good amp that's been well recorded should be negligible," which on paper seems to hold a fair amount of truth to it.
However, I'd argue that this only holds true if the only difference between a model and the real thing is some mysterious "realism" or "warmth" or some other nebulous vague authenticity that one has and the other doesn't. While that may in some ways be true (and very few modelers I've played "feel" like a real amp, so there's something to be said there for playing response and how it inspires you as a player) my experience has been that this ISN'T true, and that there's usually some fundamental differences in frequency response.
My PERSONAL experience has been that the high end response of most modelers is quite a bit different from most "real" amps; they're a bit fizzier and hairy, and that the highs in particular are an area that current-gen speaker simulation hasn't quite gotten down. Additionally, the midrange doesn't usually seem as clear to me - modelers tend to sound a little blurred by comparison, when relying on speaker simulation.
Part of the problem too is that Line6 in particular seems to over-gain their amp models, so a lot of players tend to use more gain than would be advisable if they were using a "real" amp.
Anyway, the fizzy highs and the blurry mids can get you into a lot of trouble in a mix - a guitar is basically one big chunk of midrange, and if the mids aren't clear and tight, then your guitars will sound a bit indistinct.
That said, we're definitely overdue for a new generation of speaker similation technology - Line6 hasn't really released a new version of their cab modeling since 2.0, I think, and there's been a lot of work recently with impulses to simulate cab models, which seems to hold a lot of promise. Some of this is even making it out of the software world and into modelers - see
the AxeFX, for one.
So, in a word, where you're mistaken is a model and a mic'd amp tend to sit in different "places" in a mix, and the combination of a good amp and a SM57 (or a nice ribbon, if you swing that way) is so popular because the frequencies it tends to emphasize sits in a mix VERY well.
