Recording a live acoustic guitar and vocal performance can be a bit of a crap shoot. Depending on the guitar and how the singer projects, you can be looking at both having too much guitar in your vocal mic or too much vocal in your guitar mics. Mic placement might improve things but you could still end up with a really cut down set of options when it comes to mix time. The EQ you need to make the guitar sound great might also emphasise a part of the vocal that doesn't sound pleasant and so on... It can be a tough balancing act of compromise after compromise. Here's a mic technique I learned from Steve Albini at his Mix With The Masters seminar, which gives fantastic isolation.
MUSICIAN, LIVE & STUDIO ENGINEER
Kildare / Dublin