I've been using the treo headset/headphones hybrid without much success. Sound would tend to come out of only one of the two earphones. To make sound come out of both, I had to pull up on the headphone jack slightly. This however would only work for a little bit (maybe 30 seconds) till it got knocked or just fell back to its normal position thereby making sound only come out of one headphone again. Anyway, my solution for this dilemma was to make really tiny balls from aluminum foil and put them in the input (I used two) until the mic jack was at the right level to have sound come out of both. It works a lot better and if it reverts back to sound coming from a single headphone I just push down slightly on it which is a lot easier than pulling up slightly. Anyway, it's a lot more consistent and stable. So if you have the problem of sound coming out of one headphone and only two when you pull up on the jack, here's a solution. Hope that helps.