Anyone know why the sound quality through my ipod interface is diminished?

[sickspeed]

i have the oem cable installed from the head unit into the glove box. its an 06 A4 with the symphony 1 system. when i listen to the ipod the volume is about 5-10 spots below where it is on a cd and the base is reduced. the adapter was installed by the dealer btw, so i didn't screw it up myself. ; ) thanks.

[Menlo S4]

I think the answer starts with the quality differences between mp3 and CD audio. Just like records (!) sound better than CDs, mp3-compressed audio usually can't touch CD quality. That's where you might be losing bass.

[surfntomm]

doubtful that its the recording if the bass is really reduced that much, especially if he compared it to his headphones or similar. Most likely what is transferring the signal to the HU is attenuating the signal on the lower end.

I dont know how the dealership hooks up ipods etc but that would be my guess.