I connect my iPad through the MINI Y-cable, and it is extremely noisy/hissy. I play the music loud enough that it is not noticeable during the songs, but between songs it is really bad. Am I doing something wrong, or does everyone have this issue?

 

Check to see if the noise is present when the item is playing on battery power....some adaptors make a bit of a hum/buzz...trying a different car adaptor may help.

 

Not sure what you mean by 'playing on battery power' - do you mean when it's not plugged into the input?

 

Not plugged into a 12v adaptor...
Some folks had a similar buzz on gen1 cars the aux in jack if the phone was also charging.

 

The Y cable has a USB part and an AUX part. It won't play without both plugged in.

 

make sure that the headphone part of the y cable is pushed in all the way. i've had the same issue with mine and it turned out to not be completley seated.

 

I had the same problem with my XM skydock and I installed a 3.5 mm ground loop isolator and it fixed the problem. (7 $ on ebay)

 

My 3rd gen iPod does not have the same issue, only my iPad.

 

Dumb question, but is the iPad volume turned way down?