I have an adapter for the headset output to take it from 2.5 to 3.5 (standard for headphones so I can listen to music). However, it only plays mono (out of one speaker), unless I pull it half way out, and even then its constantly cutting in and out of both speakers. I know its not the adapter, it worked on perivous phones and I tested a new adapter with the same result. Is this a problem with this phone, or should I take it into sprint to get it fixed? Is there another solution? Thanks.

It's the wrong adapter. The easy way to tell is to look at how many "rings" it has. It should have 3 black rings and 4 metal ones. Bet yours doesn't.

You can get the right one from places like sedio and ppc techs.

You're right, mine only has two black rings. Whats the deal with that, shouldnt they all work? I found the right one online, do you know if there is a store that would carry the right kind?

Yep, that's a stereo (2 channel) adapter. We need a stereo + mic (3 channel) adapter. I don't think that Radio Shack carries them, but you could check. Otherwise online may be the best answer.