Stock picture from Colourbox
See, mix philosophy is you start with the best performance you can get, captured as cleanly and accurately as you can get. Nothing wrong with audio manipulation for artistic effect; George Harrison was playing all kinds of tricks with tape speeds and overdubs and Abbey Road is one of the great albums of all time. What you don't want to be doing is trying to fix basic mistakes, like a singer who forgot the notes or a broken microphone.
Douglas Morrison Little Theatre
When I became ME for a small community theatre I had to learn to mix. And I turned to MIDI -- synthesized instruments -- to produce multi-part songs I could practice mixing on. And nothing wrong with that. TV shows had to get by with largely synthesized music, so did musical theater, so did games. A full symphonic orchestra is expensive. And even when you've got a half dozen real musicians in the pit, the demands of a Broadway score are such that two or three of those musicians will be playing synthesized instruments on a keyboard.
Thing is, there's a human factor about actual, physical instruments. They have more flexibility and can turn in a more nuanced and detailed sound. But more than that, there's a sort of essential honesty that comes through. Even the makers of a software and hardware package designed entirely to substitute for a pit orchestra (OrcExtra) suggests you replace as many of the built-in parts as you can with live players. Even just seating one trumpet beside the keyboard player who is operating the software provides a better experience for the audience.
insaneintherain, YouTube capture
And then there's these people. There's plenty of people, again, who get perfectly good result playing their chosen instrument against canned background tracks. But there's a sort of bragging rights in being able to say you played "All the parts" -- and there's people who do. A surprising number of them, in fact.
Odd thing is, though; often the drums are canned. Drums are expensive and take up a lot of space and are hard to record. So pre-recorded drum loops are not uncommon even among people who can play three or four different families of instrument. Same will sometimes go for strings or even bass. And of course piano; these are almost all legitimate keyboard players, but an actual piano is large and heavy and expensive. So they play a piano sound on a piano-like keyboard.
And that's where that mix philosophy starts to get weird. Someone like Carlos, he's clearly playing through the entire piece for each part he plays. Others, they are just as clearly making take after take until they finally get a useable one.
And from there it's a tiny step to editing out the fumbled note or even slapping a layer of autotune on the whole thing. And that's where it gets weird. See, the sound of an instrument is manipulated all the time. A trumpet in the rehearsal hall sounds a lot like a trumpet on a recording (but even there, expect compression and reverb...there's a reason there's so many buttons and knobs on a mix console). The rock drum kit, on the other hand, sounds very little like that in life. It is arcane application of specialty microphones and a lot of processing that gets that final distinctive sound.
Point being I don't see there being a bright line. And when it comes to recording, being able to say you played the trumpet part on an actual trumpet is really just bragging rights. But what happens if you re-pitch and sonically alter a recorded trumpet in order to get a french horn part out of it? What if you chop up a crumhorn performance in order to fake a bagpipe? Heck, can you even say you played "guitar" on a track if you used a ukulele and processed it a lot? And who cares if you do?
One problem I have is the same one that "fix it in the mix" points to. And that is when you chop and manipulate a take, modify and re-tune a sound, you are taking away from the music instinct and integrity of the moment of performance. There are decisions you make as a player that only happen in that context. They just don't present the same when you are down at the sample level hand-editing a waveform.
Basically, you risk taking the life out of it when you manipulate a recording in certain ways. And worse; if you had to resort to technological trickery to record it in the first place, that life was never there in the first place.
But...is this wrong in other ways? Is there a dishonesty in doing this kind of manipulation? And a dishonesty to what, and whom?
(The other thing I'm finding very odd is after decades of doing live sound and obsessing about mic placement, I'm recording my own stuff with basically any old microphone and....fixing it in the mix.)