CAR Free Air advice

[evil0ne]

I bought an E39 M5 and want to redo the stereo but keep it stock looking. The factory had an option for free air subs and I want to go that way but I'd like some advice on some current subwoofer options as I've been out of the game for too long.

And for those that can't live without pictures my apologies but these are the best I have for now.

[ajholt7]

There is a marine one by Wet Sounds.
http://www.wetsounds.com/pages/products/XS-10FA.html

I have this one in a 10". It sounds pretty good as a free air.
http://www.kicker.com/compvr_aluminized

[youatigenow]

Here is a link to a company that does BWM sound systems. I had some of thier speakers in my old E46 and they sounded great. They are pricey but very good quality and great customer service.

http://www.bavariansoundwerks.com

[ajholt7]

Sorry for my post above. I was driving when I replied. Didn't realize the great big CAR part.

[chpthril]

Free-air (infinate-baffle) theory holds true for a car as it would a boat. You need complete isolation between the front and rear of the sub. A sealed enclosure trumps free-air and ported trumps a sealed.

Does your car already have an amp to drive the sub? If not, I would bypass the infinite-baffle and do an encolsure. I have (had....as I blew it) an old JL 12 in a 1.0 sealed in the boot of my V-dub brigded on a Kicker KX150.2. It hits (did hit ) pretty hard as it is loaded off the back of the back seat.

A 10 or 12 in a slim-line box with 200-300 watts rms in the trunk would sound great and not take up a lot of space.

[ds@earmark]

Given that enclosed subwoofers, like acoustic suspension/sealed or bass-reflex/ported, are generally better...many BMWs are unique in that the rear deck and rear bulkhead are solid metal and very well sealed from the cabin other than an opening for the subwoofer. So in this rare case an infinite baffle does extremely well plus solves an installation challenge or two. Its really hard to get performance out of an enclosed woofer sitting inside a totally sealed off infinite trunk and then venting the bass energy through a small 50 sq. in. opening into the cabin. Another effective option is a bandpass design where the final and singular vent is partially protruding out of the enclosure and sealed within the factory opeining. This approach serves to completely eliminate the trunk displacement and resulting losses. However, its a very complicated build from both a acoustic design and structural standpoint. So back to the infinite baffle in this particular vehicle. Just use a JL Marine true IB woofer and apply a thick adapter plate to seal and couple the woofer to the factory opening. Also, seal off any small wiring pass-throughs that may be concealed behind the trunk liner. You'll be impressed.

David
Earmark Marine

[ds@earmark]

Given that enclosed subwoofers, like acoustic suspension/sealed or bass-reflex/ported, are generally better...many BMWs are unique in that the rear deck and rear bulkhead are solid metal and very well sealed from the cabin other than an opening for the subwoofer. So in this rare case an infinite baffle does extremely well plus solves an installation challenge or two. Its really hard to get performance out of an enclosed woofer sitting inside a totally sealed off infinite trunk and then venting the bass energy through a small 50 sq. in. opening into the cabin. Another effective option is a bandpass design where the final and singular vent is partially protruding out of the enclosure and sealed within the factory opeining. This approach serves to completely eliminate the trunk displacement and resulting losses. However, its a very complicated build from both a acoustic design and structural standpoint. So back to the infinite baffle in this particular vehicle. Just use a JL Marine true IB woofer and apply a thick adapter plate to seal and couple the woofer to the factory opening. Also, seal off any small wiring pass-throughs that may be concealed behind the trunk liner. You'll be impressed.

David
Earmark Marine