If you have vocals recorded in mono, and expect to mix them with no panning (centered at 0), would you render them into stereo, or render them as-is in mono? (They are dry.)
That relly depends on what you are doing in the mix. Are you using these vocals as backing voclas? Are these vocals just one lead vocal recorded multiple times? Are the vocals from an actual signer or are there from an a speaker, or an actor, or a narrator?
It really depends on what your doing, and who you are sending them off to. I don't know your scenario but I will give you some guidelines:
1. Mono backing vocals- print these as one stereo backing vocal and keep the original backing vocals together
2. Different lead vocal takes- keep one and leave it mono, unless you want to use a duplicate for certian parts of the song
3. Rap vocal- usually you have one mono vocal and a duplicate as sort of a hype man for certian phrases.
4.Actors, speakers, narrators-mono, enough said.