Box Subwoofer box - New version

[agarabaghi]

Well the last box I built got water damaged from the inside. I guess more moisture than I expected creeped in from the port. I deceided for the environment of a boat that sealed would be better. So i upped the driver size to 12" from 10" and went with a 1.3ft sealed box.

Also added a pair of rev8s to the tower to accompany the pro485



Will post more pics when my imageshack app starts working again lol

[JimN]

Originally Posted by agarabaghi

Well the last box I built got water damaged from the inside. I guess more moisture than I expected creeped in from the port. I deceided for the environment of a boat that sealed would be better. So i upped the driver size to 12" from 10" and went with a 1.3ft sealed box.

Also added a pair of rev8s to the tower to accompany the pro485



Will post more pics when my imageshack app starts working again lol

I would use a waffle grill- when people and things are tossed around, something is bound to go through the cone. Looks good, but it isn't safe from toes, skis, etc.

[agarabaghi]

Well we re did part of the system after the last box didnt hold up to the moisture. The previous box was ported with an XCON 10" on 2x apsm 1300 strapped together. It was loud for sure, but the port allowed too much moisture in and destroyed the box. I decided to go with a little less power and bit more cone area. Sundown SA12 subwoofer and 1 apsm 1300 @ 1ohm. The box is sealed this time, and i use truck bed liner and rubberized underbody spray. The outside was them primed with bathroom primer (says it worked in high moisture environments) and then painted with water proof spray paint, and finally carpeted.

In boat speakers: (4) JL Audio M770 7" drivers
Amp: Wetsounds Syn 6 (waterproofed arc audio amp basically)

Subwoofer: (1) Sunday SA12
Amp: Audiopipe Apsm-1300 1000 @ 1 ohm

Towerspeakers: (2) Wetsound Rev8 - 8" midbass driver + 1 HCLD horn in each pod
(1) Wetsound Pro480 - 2x 8" midbass driver + 1 HCLD horn
Amp: Wetsound Syn 6 (channel 5 + 6 bridged) 600 x 1 @ 4ohms
Audiopipe APMR-1504 bridged 230 x 2 @ 4 ohm

[JimN]

Originally Posted by agarabaghi

Well we re did part of the system after the last box didnt hold up to the moisture. The previous box was ported with an XCON 10" on 2x apsm 1300 strapped together. It was loud for sure, but the port allowed too much moisture in and destroyed the box. I decided to go with a little less power and bit more cone area. Sundown SA12 subwoofer and 1 apsm 1300 @ 1ohm. The box is sealed this time, and i use truck bed liner and rubberized underbody spray. The outside was them primed with bathroom primer (says it worked in high moisture environments) and then painted with water proof spray paint, and finally carpeted.

In boat speakers: (4) JL Audio M770 7" drivers
Amp: Wetsounds Syn 6 (waterproofed arc audio amp basically)

Subwoofer: (1) Sunday SA12
Amp: Audiopipe Apsm-1300 1000 @ 1 ohm

Towerspeakers: (2) Wetsound Rev8 - 8" midbass driver + 1 HCLD horn in each pod
(1) Wetsound Pro480 - 2x 8" midbass driver + 1 HCLD horn
Amp: Wetsound Syn 6 (channel 5 + 6 bridged) 600 x 1 @ 4ohms
Audiopipe APMR-1504 bridged 230 x 2 @ 4 ohm

If you build more boxes, you can also seal the MDF with polyester resin or epoxy. It doesn't have to be a thick coat but it does need to be continuous, with no gaps. Also, you can use Titebond exterior wood glue, which isn't affected my humidity (might be a problem if it's really wet, but if it's well-sealed, probably not). I did this for a workbench top and at one point, spilled Acetone on it- nothing happened.

[agarabaghi]

The 1st box we used epoxy to seal it, but of course i didnt seal the inside and since it was ported the moisture destroyed the box.

[02ProstarSammyD]

epoxy over poly imho. Looks good though! Was thinking about doing this in mine.

[EarmarkMarine]

Any coating is going to be micro-porous and eventually wick up moisture through the protective sealant.
Polyester fiberglass resin is okay. Mixing the catalyst too hard or too cold makes a difference. Epoxy resin is a little better. Polyurethane truck bed liner (thick and professionally applied) does a good job.
A solvent based constructed product, MDO, MEDEX, etc. will be far superior over a water based MDF.
The biggest difference maker is in the execution of the enclosure. Right glue. Radiused corners for thicker sealant coating that doesn't shrink back from the edges. Completely filled and sanded smooth staple/nail/screw depression and seams so there is no micro foothold for the mosture to sink in.
A very important step is to elevate the enclosure off the sole with a few polymer risers to provide for drainage and evaporation. Besides, who wants to create a mold and mildew trap.
Marine-grade rubber-backed non mildew carpet. An automotive carpet or trunk liner will hold moisture in. Use S.S. staples. Use end caps and silicon seal all carpet or cap seams.
Gelcoat applied over MDF would crack almost immediately.
MDF naturally expands and contracts with changes in humidity. MDF is not airtight as is. With 50 psi of vacuum you can pick up one piece of MDF through another MDF piece. The direct water exposure is not as bad of an issue as the repetitive wet/dry cycle. After the tiniest bit of initial damage (too small to see) the subsequent breakdown and expansion of MDF really takes off with each cycle....until you eventually have MDF soup. The bottom seams usually fail first within the first season. Although a carpet wrapped enclosure can hide the failure for several seasons the damage is done. Try this. Measure your enclosure after the initial build. Measure it again after a year. If the dimensions have changed, regardless of the appearance, the enclosure is toast. All it takes is a couple of pin hole failures and the woofer loses the damping from the enclosure. The bass sound quality changes and the woofer mechanical suspension begins to fatique prematurely.
Again, with the right execution and materials, even with all the above information, an enclosure can last.
An off-the-shelf automotive box using cheap MDF from China won't make it a month in a boat no matter how you try and coat it. Heck, they don't even last in cars.

David

[02ProstarSammyD]

what about putting some leveling feet under it or just rubber feet? Half of my problem with doing this is I wash my boat out pretty much weekly and thought the same thing about water pooling.

[EarmarkMarine]

Rubber feet, HDPE pads, any non-wood polymer or composite riser, all the same to me.

David

[JimN]

Originally Posted by EarmarkMarine

Rubber feet, HDPE pads, any non-wood polymer or composite riser, all the same to me.

David

How fast do you want it to move with that HDPE on the bottom? My guess is that it will be like the "pull the table cloth out from under the plates and vase" trick, on hard acceleration.