Yea... all the stuff I record
acoustic guitar and vocal and leave at that really winds up being mono.
I add reverb to the overall sound, just enough to make it a little more full, but not so much that you can really tell unless there is a dramatic change in volume somewhere in the piece.
Of course, as I believe the other Glen said, you probably won't be content with that. But I've gotta tell ya - this sounds like it comes back to the polishing of the turds. If the performer and material were enough to hold your attention, you may very well not be scrambling for ways to make it sound "fuller". Passages with minimal playing and vocals should sound like they are placed there for a reason - not just because the vocalist's sound is thin and the guitar part is bland.
Guess this isn't the place for a rambling commentary, but too late! Of course, I suppose as engineer/producer/mumbledeefoo it isn't your job to tell the artist "The mix sucks cus
you suck!"
I've had problems with this before myself, and close to home... my brother recorded some original material but decided to have his girlfriend (an egomaniacal crazy woman) sing it because she "sings like the angels on high". She was all over the place in terms of dynamics, placement around the microphone, etc. When we were done, I played it back and she thought it was awful, and immediately blamed me. I said nothing, knowing after the first five attempts to get her to cooperate with the mic positioning, etc., that this wouldn't solve any problems.
So, long story short, try some reverb and stereo panning, but I think that's all you are going to be able to do for this mix. If it sounds weak, you can't work miracles - and any blatant tricks to try and beefen it up are probably going to be glaringly obvious, unfortunately.
, use reverb to fill the stage. Not so much that you're swimming in it, of course, just enough to thinken the overall mix and fill the holes a bit.
