klover..
I don't really know the EMX powered mixer.. but, If it has a headphone jack get a good quality headphone. Like Sony's or AKG's Recording line.. (Closed Air Sets) They will run somewhere near $150.00 and up. They have the best quality to hear with.
(I personally will use wireless "In Ear" Monitors with a bass "Thumper" if I can The singers love the "Thumpers".) *Also protect them with your life if you can afford the systems!*
I guarrentee you, they will sound better than your speakers& and your total sound will improve overall.. Also, set up your mix with them to your liking, and THEN set the room from there. I use headphones to baseline all my channels on my console. THEN, I do my room from my outboard. It really makes my life and world easier to deal with.
I wish ya luck and hope ya like the Yahamas.
the seperate vocal processor is up to you.. I personally recommend two companies right now.
Lexicon or TC Electronics. They both have great new products that are priced affordably.
Oh yeah, I forgot Yahama Just released a NEW Product too for Vocal Effects..
Behringer's stuff isn't worth the trouble right now if ya want it to last.