LG VX-8100

ok so i got the mp3 player to work sounds great out of the phone but i bought an adapter to make the audio go through my home system (which is a bugtime system) and it goes through but it only comes out one speaker and is really attenuated, when i hook up the headphones it comes out 2 speakers, still very low volume, i can still blast my house system and it get's loud near max volume but still only comes out one speaker and the sub im using stero wires, left n right, does anyone know of a direct 2.5 mill jack too stereo or even if it will make it come out bolth speakers. any info would be greatly appreciated, thanks