Hi sirs... need your help and expertise on my car audio. Im not even sure if its the setup thats the problem or the HU itself.

Basically my HU is a pioneer DEH 2950... entry level HU with aux and mp3 in-dash. My main source of music is my creative vision m player which I plug via a 3.5 to 3.5 jack connector to the HU. my jack connector is already gold tipped so its a high end jack.

Anyway, sound is really good (together with mu subs, amp, and custom EQ in my player) however I noticed that in some songs (or probably most of the songs which I fail to notice since it's too negligible already), some instruments can't be heard. Even in some songs, the voice can't be heard.

When I half unplug the jack from the head unit, the missing instrument would be heard, however compromising the stereo sound turning it into mono.... but again the missing instrument sound or voice will be heard.

Just to give you some examples, when the jack is fully plugged to the HU, I won't be able to hear the guitar solo in my sharona, or the harmonica intro in crazy (by aerosmith).... I half unplug the jack, then I will be able to hear the solo and the harmonica (but the rest of the song will sound like mono)

I hope I was able to explain the problem clearly and hopefully you could suggest solutions to this problem.

Thanks!