My sim rig setup includes some rather powerful studio monitor speakers, because I like my racing LOUD and realistic! The downside to this is that if I press the push-to-talk button to participate in voice chat, I am blowing the ears out of everybody in the race.

This is the solution!

When this checkbox is ticked, the iRacing-TV controller will automatically mute the selected audio device whenever the push-to-talk button is held down. When the push-to-talk button is released, the selected audio device is automatically un-muted.

Select the audio device to mute/unmute. You should select the same device that the iRacing simulator is using to play audio.