Cut the Muff

In short, to cut off poor quality audio.

To "cut" something means to remove or eliminate it and "muff" is short for muffle or muffled. In this case it is in reference to audio.

The idiom "Cut the Muff" is an amusing way to tell someone that their mic or audio output is muffled or unclear.
"Very muffley, very cutty. Cutty muff. Cut the muff." - Timmaaay (Obsolete Punx)
Get the Cut the Muff mug.