Jim, when I eliminated a mixer from my system, I added a TC Helicon Harmony-M, which I fed directly into the Line In of my PSR-S950. The harmony-M had it's own effects, which in combination with the keyboard's mic effects, were just incredible - far better than when I was feeding the same mic directly through the mixer. And, as you have discovered, the Crown CM311A is probably among the best headset mics for live entertainers. A lot of folks have tried headset mics and went back to using their old, hand-held mics, but most that tried the Crown CM311A never looked back.

Good luck,

Gary