Speaker separation versus listening distance??


Is there a formula for separation distance between speakers, versus sitting/listening distance?
route30
+1 on both preceding comments and consider as well that angle (toe in or out) can be non standard as well. I have found that my room requires on speaker be more than 5 degrees different from the other to center the sound image.

I would have to agree.Starting of with the equal distance idea is a good place to start.If you have 10'between speakers ,then use 10' of distance to you.This is just to start out with, although a lot of people use this in their final setup.
Agre with previous posts, but have also found this to be a useful guide:

http://www.cardas.com/pdf/roomsetup.pdf
I like the speakers slightly closer in my opinion. Everyones different, and depends on the speakers.