Sub without a box?

[mach189]

I know I may be crossing the line with this post but does a sub always need a box? Depending on how my speakers sound with an amp I may buy an 8" sub like the Polk MM2084. There is an area about 12"x12" that's cut out of the frame in the trunk behind the rear seats and I was wondering if I could treat a sub like a coax and install it there? Space is at a premium in my trunk so this idea appeals to me. I look forward to any input. Thanks.

[michael_w]

I'm not sure if it's what you're describing here but yes you can run a sub without a box. All you have to do is have something seperate the backwave that is produced, so basically some kind of barrier that you mount the sub into.

Maybe this will help explain things.
Infinite baffle link

[mach189]

Yeah that's exactly what I was talking about. The "rear deck" installation is how I was planning on it if I got a sub. Could I use the Polk MM2084 in this situation or would I need a sub designed specifically for this?

Thanks for the info.

[neomagus00]

I know I may be crossing the line with this post but does a sub always need a box? Depending on how my speakers sound with an amp I may buy an 8" sub like the Polk MM2084. There is an area about 12"x12" that's cut out of the frame in the trunk behind the rear seats and I was wondering if I could treat a sub like a coax and install it there? Space is at a premium in my trunk so this idea appeals to me. I look forward to any input. Thanks.

what line could you possibly be crossing? :)

infinite baffle is great in theory, very difficult to pull off accurately in practice. it means that, once you mount your sub into its hole in the rear deck, you have to seal the cabin of the car from the trunk, and make it completely airtight - in effect making the whole trunk your box. this is, as you may imagine, rather difficult.

an 8" sub generally requires very little airspace, and you could potentially build a sealed box to spec, then simply bolt that sealed box to the rear deck (where there's an existing hole). that gives you the sealed box on the sub, but keeps the whole assembly out of the way.

[98thumpin]

sounds good but hard to pull off

[mach189]

an 8" sub generally requires very little airspace, and you could potentially build a sealed box to spec, then simply bolt that sealed box to the rear deck (where there's an existing hole

That's actually a really great idea. I don't know why I hadn't thought of that already. Basically I want my car to look stock.

When I said "crossing the line" I was referring to the idea that subs must have a large box and take up alot of space. I was just kidding of course.

[iworkfortweeter]

theoretically possible, yet not the best idea ever...you will need a sub specifically designed for this application, and do some serious reading pertaining to the "infinite baffle" theory described earlier. i would just build a box, but that's a personal matter.
in any event, good luck!

[MacLeod]

Nothing wrong with using a sub IB as long as its designed for it. Scott Buwalda ran his 3 12's in his old Altima free air and never seemed to have any trouble cleaning up at competitions.

The 300M that I keep raving about also runs 3 10's free air and has no trouble hitting that 25 Hz thump on the test disc. But these subs are designed for free air.

[neomagus00]

in the 300M's context, however, 'free-air' is just a misleading euphimism for 'really really big box' aka 'the trunk'...

[mach189]

I kinda found out the answer to my question yesterday. My family went to eat with my grandmother and I looked in her trunk for something and saw a 10" "free-air" sub. It's a '98 lexus gs300 and the sub is setup pretty much the way I was thinking about doing it except the hole in the trunk fits a 10" sub perfectly in hers whereas I would have to fabricate something to make it fit in mine. Thanks for feedback guys.

[ward91]

do you mean using the boot as a giant subwoofer enclosure like 6x9's ect

[PaintballFREAK]

ive tired that actually

[cult4d5]

how about a piston sub?

edit: wow this is an old thread lol. didnt catch that til just now

[20hz]

how about building a clamshell isoberic (2 speakers with the cones facing each other) with that the driver only needs 1/2 of the needed cabinet size .
But if thats still to big a freeair designed speaker using the trunk as a cabinet is probebly best , just be sure the the sound from the back of the speaker is isolated from the front .
You will probebly need a large equalizer to smooth out the sound .