[rbtamms]

Dear Fellow Members,

I have a base audio in my 2011 328i Sedan & I want to upgrade my sound system. I saw a DIY here where he added under seat subs. Is it doable in my car? Is there a space for the sub housing to fit in?

[ctuna]

There are speakers that will fit.
but unless you do amplification and some rewiring and eq compensation
it won't turn out right.

Read the following link and especially the part describing the base stereo and
solutions for it.

The system you have now has 6.5 under the seats and no amplfication(other than head unit power) the suggested
replacements are 8 inch and with the right amplification can provide plenty of bass.
Do not get hung up on subwoofers before making a balanced higher quality system.
I am talking about the kind of subwoofers you put in the trunk.

http://www.e90post.com/forums/showthread.php?t=641323

[mathematics]

On your year car, the subs are a pain to get out. They used to be screwed into the enclosure and easily removed. Now, you have to cut them out with a jig saw or heat it with a heat gun and pry it out. It is epoxied in all around the edge. Jehnert and earthquake (might be a few others) make a replacement sub that fits. You would need to tap the signal from the sub harness and run it through the likes of a JL Audio Clean Sweep in order to fix the EQ issues. Then from the Clean Sweep you'd output to amp(s) and hook up your new speakers (subs, midranges, tweeters)

[rbtamms]

Thanks for the reply guys. I didn't know that I have subwoofers under the front seats...

Now, I'm starting to learn more about audios...