sorry for my delay. I'm pretty busy in my job right now. I switched the noise suppression off but I played a bit with other values - especially with the gain. But when I pull the gain down Mumble amplifies and when I pull the gain up Mumble reduces the output. The result is an unusable input signal on the transceiver's input. It's either too loud and the transceiver throttles it or so quiet that it should be amplified but there's no way to.
I'm still looking for a way to set fix audio levels without AGC 'n stuff like that.