[App_rpt-users] MASTR III

I don't want this to sound like a dumb question and I've searched all over with really no luck. I've also tried several things but I'm looking for "clean" audio. I've done this a million times on Motorolas so why doesn't this work on a GE? Does anyone have experience with an RTCM and a MASTR III? I have tried to inject audio into every point I can find in the manual and can't make it sound "right." There is a good write up on repeater builder about interfacing a controller with an M III but when I follow that it sound REAL NASTY. Any tips would be greatly appreciated.