Nah, don't be sorry. They're all sensible questions.
I suppose the answer is a blend of preference and blind faith.
Say you're into Metallica. Do you take Ride the Lightening or the Black Album as your reference?
They're both very different and most people probably have a preference, but then they're both huge selling, viable, commercial products.
Neither is
wrong-They're just different.
I suppose you can't ever know how something
should sound, because every recording you ever hear is subjected to your gear, your room....even the shape and size of your head!
Basically pick stuff that you like the sound of, get to know it on your speakers, then try to replicate it or at least use it as a reference.
I love late Queen productions. I've probably heard certain tracks on a few hundred systems over the years.
Each playback system is different, but I still know I'm listening to a damn good well balanced mix, you know?
PS: Not being a dick at all, but the word 'source' in your OP would suggest either instrument or recording medium to me.
I'm only saying to avoid confusion.
