Don't think it's an incomplete connection...that buzz is much louder. Id' describe it as a high hum. Noticed this BEFORE iOS5, so I'm not gonna lay the blame on it. Things I have noticed (and wonder if anyone else has, as well):
1. If a particular track has album art on it, I find the hum more pronounced.
2. If I listen through USB only (NOT CONNECTED), there is NO hum, but track selection is much less convenient.
3. No hum through bluetooth or over speakers in general (if only listening to radio).

Anyone else experience this? It's been bugging the hell out of me recently and almost exclusively do BT now, even though I really miss the album art/ease of navigation.

 

It's interesting, because I get a similar sound when I use the plugin feature but not with USB/Connected/Album Art.

However, I'm getting slight distortion in the right channel on some tracks, and I'm also losing the left channel from time to time. The left channel thing is definitely a connection issue, because if I wiggle the plug in the base of the phone, it improves.

 

I have the hum when playing music through the plugin feature, but not through the multimedia/USB

 

Got an update for Pandora today, but not sure if it'll effect playing through the MINI yet.

My speakers don't hum, but they do continue to hiss constantly, even when the engine's off and the key's out of the ignition.

 

Yay! I looked at the update info and it said it should fix Mini Connected issues. Let us know how it works when you get a chance to try it!

 

Just picked up my 2012 MCS. Iphone 4s is working well so far with the mini connect + nav setup. twitter, facebook work fine. ipod interface with album art & movies are fine (via Y cable). Office: able to call and review/edit contact information on screen. Have not tried pandora yet. Using Y-cable 61-12-2-179-623.