I have an IC-7100 and am using mumble fairly well. Here's some of the issues I've had and see in helping others:
- I always make sure I have my rig turned on before turning on the rigPI itself
- No other ham software should be running when mumble is running (FLDIGI, WSJT-X etc)
- Do you have SQL on or off?
- In "Set > Connectors > USB Audio SQL - is it set to "OFF (OPEN)" - this will exhibit constant sound (static if you aren't hearing anything on the frequency)
- Make sure your audio device on the RigPI is showing the 'USB Audio Codec" as defult
- In Mumble under Audio configuratino makes ure the Input is set to the ALSA > USB Audio Code and same thing in the Audio Output
What version of rigPI are you running? i'm on 1.05 and I understand there was a performance improvement with that with Mumble.
What issues are you hearing about when you transmit?