I’ve also had issues with distorted sounds on my G35 headset. The bass during dialogue is distorted and really unpleasant (especially for charr) and turns into a garbled mess during large scale battles with a lot of bass.
Also, switching the headset from surround sound to stereo causes the sound to only play through the right speaker.
I’ve installed the newest drivers from logitech and my motherboard with no success.
EDIT: Just started playing tonight and my audio issues have disappeared. I did not update or touch anything since the last time I logged in but everything sounds clear and crisp now.