Originally Posted by Rob///M5
How large a sub can you feasibly put there? You already have 8" speakers under the seat, so anything smaller than a 10" is pretty redundant, no?
I'll look to put a JL 10w7 in a custom box in the trunk, cover it with OEM carpet and blend it in to either the seat backs or rear side of the trunk so it's basically invisible.
To me the B&O sounds pretty darn good, could just use some real low end to round out the sound.
Somewhere around 8+ , it's not just about the size of the subwoofer itself but also
its response and material/fabrication.
The B&O does have some issues when it comes to lower frequencies where it just doesn't sound very well defined and "dry" . For the highs the tend to be somewhat distorted and sometimes have a slight un-natural sound to them.
However having said all of this I am spoiled from my prior life and cars (owned a car / electric shop back in Germany) and therefore am likely not representative for the majority of owners
Putting a sub in the trunk seems to be an easy solution but does have some challenges as you probably need to open the hole in the rear bench used for the ski pass through. Also if the subwoofer box is not molded into the side it will look "foreign" and I always want to maintain OEM look and finish .
Just to give you an idea
This was the install in my X5
A few pics from one of my 335's
and another 335