[quote name='Happy Jack' timestamp='1329514914' post='1543860']
Reverb?
Interesting idea ... I'd have thought that would make things muddier and even harder to hear clearly, but I've never tried it so that's a pretty uninformed guess on my part.
[/quote]
The reasoning goes something like this - if you use foldback on your voice with no colouration you hear it at the exact same time when you're singing and the moment you stop singing, the foldback mutes. With a slight reverb you can more easily discern the difference in your voice rather than just what you're singing at that precise moment.
Could be wrong though...