Try panning them ever so slightly off center to each other and you may notice it open up a little and add more sonic space to the mix.
If you have time to experiment, run your guitar part or vocal part through a delay unit with a slight amount of delay and then pan the original dry signal to one side and take the effected signal to the other side with slightly different eg settings. Now put the remaining track straight up the middle and see what happens!!
Lots of different ways to do it! If you put both tracks straight up the middle there will be no sense of stereo seperation, basically giving you a mono recording (unless they were tracked in stereo)
Anyhow, no rules here just play around alot. Try chorus's, delays, splitting the signal into two channels with different eq settings, split the signal and compress one part until it is pumping and run the other dry signal normal and pan them l/r, try using a flange............so on and so on...................
What style of music is it? Where is the energy in the track? (Folk music may have more vocal, for example, while punk may have more guitar. These are all things to consider.)
I love this type of recording, where I can fill the audio spectrum with just voice and guitar. But mono bores me. If the guitarist is right-handed, I might pan the guitar left at about 10 o'clock, so that I am "facing" the player when listening to the monitors.
If the guitar wants to be loud, I may balance the track by pulling the vocal to the right at about one o'clock. Or try recording the guitar in stereo, and leave the vocal in the middle. Last week we did some acoustic recording in the kitchen, with two mics on the guitar and a mono, omni "room" mic in the doorway to the living room. Big fun. It's all good.
I've heard a guitar vocal placed in every way you can imagine. I prefer the guitar panned 9:00 and the vocal up the middle. It's rare that I want to pan a vocal, even slightly. I find that weakens the integrity of a mix.
Having a center balances us, and keeps us feeling comfortable when listening in the stereo field. I'm not a huge fan of pure symmetry in a mix, but I do feel you need to anchor the listener. The vocal in the middle will do this.
The panning of the guitar goes along with the mental image that comes to mind when you think of a player holding their guitar. It also gets the guitar out of the vocal, and keeps it from being a mono mix.
I think a mono mix would be the next best solution.
These are my preferences. It does not make them right. But as I outlined,I do have very specific reasons for preferring them, which does make them right. Just make sure that when you decide what you prefer that you too have specific reasons why. Then you'll be right too.
I'm with Mixerman 100% on the mono thingy. Stereo is interesting when you want instrument placement to be a feature of the song, or you have multiple instruments in the same range, or if you have phasing problems between two sources.
But for a singer/guitar combo, there is nothing wrong with mono. In fact, it has some distinct advantages, like perfect balance thru any system, and nobody can mess with the mix.
Mono mixes are also easier to create; switch to mono and disconnect one of your speakers (very important to mix on one speaker if possible).
Okay, I tried both ways, and what I found with the panning was it didn't make too much difference if I panned them slightly, and if I panned both of them enough to make it noticeable, it didn't sound good because it was so unnatural.
So, the conclusion I'm drawing for the time being is to simplify life and go mono on this one.
Side note: I listened to an album I like with just voice and guitar (Rosemary Lane by Bert Jansch), and noticed that voice and guitar are panned ever so slightly. But I hadn't noticed it until I listened for it.
Thanks for the ideas - gave me useful stuff to think about.
When I came across this question it reminded me of something I did that worked very nice...
If you hate mono but feel almost stuck in the middle (pun intended) Stereo the guitar. On one side (right as your facing the speakers) cut the guitar highs slightly. On the other side, cut some of the guitar lows. If your using verb on the vocal use delay on the guitar or vice versa...
Work to make the effects, on both the guitar and vocal "musical"...In a case like this, less is more... This way, the effects will add a nice finish, while keeping the vocal and guitar from running all over each other...