I used to get that problem every so often. They couldn't understand me only when I talk. My own solution was simple.......move my mouth back from the mike to the furthest point where the mike will still pick up my voice. Depending on the mike you use, it actually takes a bit of conscious effort to remember to stay in that "clear" zone.
Mark
My mic is a headset mic. This is not possible. The Yamaha S950 and some other Yamaha models come with a compressor and a noise gate in the Talk settings menu. I have both of these switched to off. I wanted to find out what compression settings might help with this problem. Thanks