Just an interesting FYI. For the last couple of months I have noticed my engine noise seemed to be getting louder even with my noise cancelling headset on (Lightspeed Zulu 2). So I have been somewhat concerned, looking for exhaust cracks/leaks, carb sync, etc. During this time my Zulu headset, which is 900+ hours old, ear seals were wearing out and splitting open in a few places exposing the foam cushioning. I finally replaced them with new ear seal pads and Walaa, my engine was its old quiet, smooth self again. I would never have guessed that a somewhat worn out ear pad, on one side only, would make that much difference.