Earl, Gary Diamond has posted a very good article at PSRTutorial on Vocal settings for PSR2000/2100 and Tyros Keyboards which can be adapted to the PSR3000.
It could be a good idea to return the keyboard to the factory settings and start again from there.
You could also try going into Function and make the TYPE standard duet and turning the Volume down to zero.
I had an annoying echo and this has fixed it.
I also had help from a friend in choosing the appropriate microphone which in my case was a AKG880m.
I hope this helps as I would like to contribute to the forum.

Cousin Ken