Yesterday I purchased a Plantronics Voyager 855 stereo Bluetooth headset, expecting that I'd be able to use it with my N800, which is running OS 2008 2.2007.51-3.

It sort of works, but the sound when playing MP3s is like listening to a scratchy phonograph record through a tin can and string. It's very tinny, with clipping and with constant scratchy noise. The same MP3 sounds great through the N800's speakers.

I thought the headset might be bad, but I tried it with a PC running Windows, and playing the same MP3 through the headset sounded fine.

Is the Bluetooth in my N800 defective? Or is this not expected to work? I thought it would either work fine or not at all, and was very surprised when it worked badly.

Nope, your bluetooth headset isn't broken most likely, but N800 is not using A2DP bluetooth profile when you pair it with headset. Search for A2DP and you will find a thread how to get stereo sound from your headset with N800.

Jaykie