Hi all,
 
Just recorded a live string quartet in Sonar X3 for an upcoming project.  I've never mixed a string quartet before.     All I've done so far is pan them each like a string quartet seating arrangement in the stereo image, and added some Hall reverb from the BREVERB 2 module.
 
Anyone have any tips or advice? 

I do some trombone quartet recording - here's what i do
 
1) before adding any reverb, see how well in tune they are. You may have to use Melodyne. 
 
2) EQ each instrument on its own track. Each instrument has it's range - bring down the edges and enrich thecenter of their timbre.
 
3) apply reverb and compression on separate stereo busses for the ensemble. I prefer convolution reverb for acoustic instruments
 
caveat - I'm an amateur hobbyist - a pro might want to add or override some of these suggests. And there is an "undo" feature.

I just read an old TAPE OP interview of Bruce Swedien and he said something similar viz acoustic instruments. You missed your calling!

Except for compression.  He said *compression is for kids* :D

well, then, i wish Bruce good luck in hearing the pianissimo passages in the string quartet while he's driving down I-95 at 70 mph with snow tires  :D . Seriously, i agree with that, unless the dynamic range is pretty wide. 

I'm a total NEWB! But doesn't it make sense that the amount of compression one needs depends upon the ability of the performers?  

This whole idea of altering the sound versus fidelity is new to me.  

Compression "squeezes" the louds and softs closer together, at least in the context in which i use it. And I'm a Johnny come lately in this myself.  I've got loud sections at 100 (just an umber I made up) and soft ones at 20. The 100s are very loud and the 20s are barely are really quiet. So i compress the 100s down to 70. Now 100 was OK, so now i have softs at 20 and louds at 70. I now raise the whole thing, and now the louds are back to 100 and the softs are at 50 and they pop right out to be heard nicely. 
 
If louds were at 80 and softs were at 40, I wouldn't use compression.  That's the etent of my understanding of compression. youtube has the rest.

Regarding compression, this post by Jeff Evans is excellent on how to set one up (properly). For general overview and typical settings for various uses (scroll to the bottom), this Sound On Sound article is useful.

terrific, metellus - thanks for pointing it out.