I've bought the bluetooth oem Palm headset, and the wired earbuds that come with the phone, but both sound somewhat digitized and low quality compared to the built-in earpiece. Seems to loose the higher crisp frequencies. Is there a reason for this? MP3s sound decent when using the earbuds... is there some processing going on that combines system/phone sounds that degrades the audio quality???

...or do I just need to spring for a more expensive accessory... Maybe a Plantronics Discovery 645/640. Any suggestions?