Ported enclosure question

[MrPerfectionest]

I am contemplating a bit of a strange setup in my 2002 Jeep Grand Cherokee. The problem is, I am trying to figure out the best enclosure that meets 4 different criteria.

1. Doesn't take up much surface area when I put my seats down (for transporting various things)
2. Still puts out reasonable amounts of bass when I am carrying three passengers with the cargo area loaded
3. Can manage to put out a decent amount of bass (i'm thinking 12-15" sub with a modest 100-200w on it)
4. Doesn't involve a lot of fiberglassing and removing of interior panels

I started with a mdf/fiberglass enclosure that was going to be on the passenger side wall in the cargo area. I removed the plastic trim there, and while I am fairly certain I can get a good fiberglass enclosure to accommodate a 12/15 (and fulfilling criteria 1,2, and 3), I am not so sure about filling in all the gaps that will be left over from where the plastic trim was, and this would drive me nuts forever.


So, my latest idea is a bit of a false floor, utilizing the spare tire well for the majority of the volume. This fulfills criteria 1, 3, and for the most part 4. What I am unsure of is 3. What I am contemplating is building the majority of the volume into the spare tire well, have the false floor rise a few inches above the current cargo floor, and in these few inches, construct a slotted port that will fire into the back seats. What I am unsure about is how this will sound if luggage is piled on top of the driver itself? Of course, I'll construct the box in such a way that stuff isn't literally sitting on the driver, but the airspace around the driver will be minimal. I also realize the seat backs will influence the tuning if they are close to the port exit. It's been awhile since I have studied enclosure theory and googling is proving to be only so effective.


Does this seem workable? Any other ideas to meet the above criteria? I had also contemplated some sort of enclosure mounted to the lift gate, but I'm not sure how well it would stand up to being opened and closed with massive sub box hanging off of it.

[Lothar34]

Can you post a pic of this spare tire area?

[MrPerfectionest]

I'll get one tomorrow or the next day I hope. But it's just a typical SUV with the spare tire residing in the floor of the cargo area covered by a removable panel.

[Lothar34]

Well you could put a regular sealed enclosure down there, but make the cover completely open on the sides (so it's held up with posts or something). Then you don't have to worry about tuning or something blocking the port. It's just like having a down-firing sub at home, but upside down. As long as you've got a couple inches between the driver and the cover it should be OK.

[v-bro]

Compound enclosures (speakers mounted face to face with one connected in reverse) produce lowest fs in smallest enclosure...(about 30% difference to closed type..).

I use a baffle in my car, protected the front and rear of the (12") drivers with perforated aluminum sheets...
This way it doesn't take much space either.

About the luggage on top, bass frequencies tend to go through flesh and bone they say.....Up to the level of "completely sealing" I think the sound will stay surprisingly good....

And why not use the space of the spare tire, most Jeeps have it hanging at the rear, maybe an idea?

[MrPerfectionest]

About the luggage on top, bass frequencies tend to go through flesh and bone they say.....Up to the level of "completely sealing" I think the sound will stay surprisingly good....

I dunno. At the moment, I have a JL 10w3 in a rather large ported enclosure (tuned decently low) with a sloped back to match the back seats, firing backwards towards the lift gate. Whenever I pile in luggage for a trip, the luggage does a really good job of nullifying most of the bass.

This is why I have the idea to have a port firing towards the front. The back seats don't offer too much in the way of resistance, but an entire cargo area of stuff seems to in my experience.