I know NOTHING about mixing sounds, so I looked at the manual and see that the "reverb" effects are on one set of controls so my question is this:
How can I add the "reverb" to just my vocal part and not have it affecting my keyboard or guitar sounds?
Thanks,

Charlie, I am not familair with your mixer but most mixers have a effects control on each chanel. in your ase that would be reverb, add as you wish.

Once you get use to using a mixer, it's hard to do without one.

John C.

PS, A guitar going through a PA system normally leaves a lot to be desired, they never sound like a guitar amp. Let us know how the guitar sound going through your X5500.