[2008.8+] Audio issues.

[Matt]

My  2.5mm 4 ring - 3.5 3 ring adapter has arrived, and keen as mustard, 
I tried it out using mplayer and my normal headphones.

To my dismay sound only came out of one earphone, it's not he first 
adapter I have tried either; I have a growing collection of adapters.
However, while I was lamenting the recent purchase, I twiddled the 
connection with the FR and both earphones started working.  I don't mean 
working as in half-pulling-the-adapter-out-mono nonsense, but working 
stereo (at least I think so).

Why might this be, the adapter plug is not bent or disfigured?
Also, how do I configure the FR speak to mute when the headphones are 
attached?


Thanks and regards

~ Matt