RE:Why does the sound occasionally sound scratchy and thin?
Poor sound quality can be caused by several issues including bad input cables, bad video/audio ports, and bad speakers. You should be able to determine the problem by trying different cables and different input ports. If this still doesn't solve the problem you may need to replace the speakers. Follow the [[Sony PlayStation 3D Display Troubleshooting#Section_No_Sound_Poor_Quality|speaker replacement]] guide to do so.