Aux on deck very quiet compared to cd. What are my options?
 

I noticed that when I play cd's they seem to make my system explode to life but as soon as I play from the aux in thing get quite a few db's lower. I know this is also very common with most aux inputs so what can I do to remedy this? add a line driver before the input to the ipod and the deck? maybe something like this:

http://boostaroo.com/store/product.php?productid=17517&cat=249&bestseller=Y

and also on a side note I noticed that when my sub is playing free air at max excursion all is fine. The cone is fine as there is no scraping when i push, and I have metered it to read 3.88 ohms so all good there. Thing is though once I put it into the ported box it becomes a fartbox.. I can hear a rattling coming from the woofer.. soon as i pop it out the box it goes away. I inspected the cone and saw the surround seperated in a spot so I re-glued it but it's still farting away in the box... it's not the tinsel leads either.. any ideas?