While the saber is powered on, hold the button and trigger flash on clash twice. The blade will go dark. Tilt the blade down to lower or mute the volume. Tilt the blade up to increase the volume. Press the button once more to exit the volume adjustment menu.
I did the same thing by accident when I first got a diamond saber. Didn't even realize I did it.
If that doesn't help, let me know?
have you tried hold-button-stab to change to other fonts?
I was just going to post both of these suggestions.