..."It's good to be the hubby"
Plug your mic into a channel of the mixer. Set all EQ flat and set gains to optimum level. (Hubby can help here, if you don't know how to do that) Send a signal from the mixer into the "LINE" input on the PSR. make sure the switch is set to "line" and not mic.
Now, control effects, harmony, and volume from the kb, and let the mixer just sit there and look nice. (and sound quiet, hopefully ! )