Question for the audio experts. I currently have two 10'' Alpine marine subs mounted under my back seat, facing the bow. Currently, they have no enclosure, well except for the area under the back seat. I'd like to build an enclosure for them. in the woofers manual, they show the specs for a sealed enclosure, but ''N/A" for a ported enclosure. Obviously space is limited under the rear seat, for an enclosure of 4.93 Cubic feet, that they recommend per woofer. Any ideas? Here are the speakers specs.

http://support.alpine-usa.com/produc...M_SWR-M100.PDF

I have always built mine in the past if sealed to the MFG's recommend cubic dims....

I just bought a couple 10's for my boat and I'm having an issue of deciding where to put them...People have said to stick them in the bilge, but I'm afraid they wont be heard....I have thought about mounting them in the glass in front of the engine compartment and trying to seal the box to the glass inside the compartment...Not sure if it will actually work..

I prefur sealed enclosures. They hit so quik n tight. Let the mid bass speakers play the. Whooa stuff. I just purchased some Jl slims. And they require little to nothing. And slam like a mofo. I was astounded on the sound

How close can you get to the 4.93? You can stuff poly fill in the box if you are close which will make the woofer think it's in a bigger enclosure then it really is. If your not close I suggest you think about selling the woofers and going with a pair of JL's or maybe even one JL. JL are know for extremely small box requirements.
You can see in the picture below the box is not much bigger then the diameter of the speaker and only about 12" deep.

Exactly.

Find what you have room for first, or what room your willing to use, and then go sub shopping.

It's like a boater that wants a big roots blower......'do I really want to cut my hatches to give them the room ?'

There are tons of choices out there including some pretty decent 'free air' subs . Just like everything else we run into with boats, you'll probably be faced with a couple compromises.

Use poly fill to expand the box volume. Make the box as big as you can allow for space, then add the recommended amount of poly fill to get the approximate volume. the closer to recommended box volume, the deeper the bass will be.

Also, you really don't want a ported box for an open air environment like a boat because you have are normally playing it louder than you would in a car.

Those are free air infinite baffle drivers. They want a huge or no enclosure. No sense in trying to put those in a box. The suspension controls the cone. Just give them the power and the will make bass.

I have 2 pair jl 10 infinite baffle subs if anybody interested. Switched to 4 10 inch slims in box that fits under the ledge of my seat n the fiberglass. I think total depth is 5 inches. I finished the front off with white plexiglass and a jl badge. Love them still have all my under seat storage. We'll half air conditioner takes up 1/3 of it. Let me know

Joe. Bill with the 42 has 4 jl 10s under his backseat free air. He has like 14 total cockpit speakers all jl. His stereo sounds amazing. Loud and crystal clear. The ladies love the back seat with subs in it. Lol

Gotcha. So putting these in a small enclosure, would not be beneficial I assume. I have never owned an "infiinite baffle" driver, but what you are saying makes sense.