Vocal bus sum to mono

[BLP]

I have been sending all my vocals to a bus to be able to add effects as a whole and control volume at once. Today I noticed when I click the "sum to mono" button on the vocal bus everything seem to sound better. Should this bus track always sum to mono when working with vocals?

 

[Bristol Posse]

Are any of your vocals recorded in stereo, panned or have stereo effects added to them prior to going to the vocal bus. Summing to mono depending on how your DAW does it and what Pan laws are active may just be making the vocal louder which in short term listening would make it appear to sound "Better"

If this is the case you probably shouldn't sum to mono as you would loose all of the panning and stereo effects, If you are recording in stereo but want to sum to mono it would beg the question why are you recording in stereo.

For me I usually have my lead vocals recorded mono and output to my summing mixer as a mono channel.
Backing vox however I have panned to various different places and so in that case I send to a separate stereo bus as I want to move and effect them separately from the lead vox

Ultimately though you should do what sounds best for your music