First, please excuse me if I'm using the wrong terms. I'm not a complete newbie when it comes to audio, but I'm no expert either. Trying to boost my knowledge and skills in this area.
Anyway, I have a compressed audio track from a game I like that's just music: no vocals. Obviously, I don't have access to the source audio files. I'd like to record vocals overtop this track: one version with lyrical vocals and another with plain speech voice overs.
My question is, given that I don't have access to the raw, unmixed audio for the instrumentals, what is the best I can do in terms of audio editing (both my vocal track and the original instrumental audio track) to make it sound as good as possible?
I understand that it'll be difficult to mix in my voice so it sounds like a studio recording since I lack the uncompressed original instrumentals. And I know that the dynamics of the voice track will be different for an actual singing voice versus a normal talking voice (for a voice over). But given a hobbyist interest in recording vocals for premixed tracks, what audio processing techniques and principles can I leverage to get the best result possible?