iPod audi quality (MDI)

[KJW]

I've just picked up a 2011 Tiguan SE.  LOVE it.

My iPod MDI connection works pretty well in general, although the first time I plugged it in, there was no audio coming through (visual interface worked fine).  Next day, I plugged it in before starting the car up, and the connection works fine.

However, the audi quality of the connection seems to be pretty poor: a lot of buzzing from various tracks with any level of bass, and I don't particularly crank it.  I've tried playing the exact same tracks directly from CD, and the audio quality is beautiful.  I realize there's always some degradation from CD to MP3, but I've never noticed it to this extent listening with headphones, home system, etc.

Does anyone have any audio experience, enough to comment on the typical quality of this sort of cable interface?  Would the direct bluetooth audio connection be of higher or lower quality?

[vwchatt]

Yes the cable is the main suspect in this case 
You can try the bluethooth streaming, but i have found that it cuts in and out with the quality of the song.
Also the audio quality of the song can be an issue as well, when on a CD the program that burns the CD equalizes the sound level over the CD. So if you have some songs that are 192K and some that are 320K, the 320 is going to sound better. Hope that helps

[KJW]

I discovered the problem for my own issue!

Under the audio settings (under Setup), the Aux setting was placed at "Loud." Apparently, this pushes the audio to an artificial level, thereby creating the distortion (both for the Aux jack as well as the MDI port). The solution was to switch the Aux setting to "Quiet," which is more of a standard output.

The audio through my MDI port is now as beautiful as it should be, clear and distortion-free!