Set up is kinda an open ended answer - it depends. On music style, the voice, etc.
I always run the lead vocal to the vocal bus. I'll usually put a delay on the lead vocal track for most songs. I'll usually put a 'verb on the bus, but w/ the mix set very dry. I used to use convolution but breverb is the first stop these days. Backing vox will usually go through the vox bus, but not always, and like Craig above get a heavier reverb treatment (on the track itself). Or I might add a vox 'verb send and route that bus w/ verb to the vox bus, or out to the master. W/ the lead vox>vox bus>master out you can bust out any number of ways. My advice is to start there and develop your own methodology for adding verb/delay. Like the rest of mixing, it is matter of learning what sounds best to your own ear and what doesn't work for you most of the time. Digital mixing is silly w/ flexiblity and it is only after trying out most of the ways to do things you cut them down to managable.
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