Hey Look No Hump-Another Sub Enclosure Thread

[Jason05216]

So this fall I've been upgrading the stereo system that came in our '15 LSV. It came with Kicker amp that is driving 6 cabin speakers and a 10" Kicker sub under the helm. I added an Exile 15.4 amp and a pair of XM9's to the tower. I also added a ZLD while I was doing the other stuff. That all went pretty smoothly other than getting the speaker wire through the tower. That was a PITA. Thanks to Brian at Exile for hooking me up with the equipment and getting me the deal on the ZLD even though I was a little early and for taking the time to help me and answer all my noob questions.

After getting everything installed and working with the amps I was able to isolate the sub and discovered just how bad it sounds. I would describe the sound as a buzz, not a buzz like something was wrong, just a bad sound. I adjusted the Kicker amp and was able to make it sound some better but still not good. The amp is just mounted on the facade under the helm. It's not in an enclosure and the area into the bow seat certainly isn't sealed . The facade doesn't go all the way to the top.

http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zpsbf8bd007.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zpsbf8bd007.jpg.html)

So I have decided that I'm going to enclose the sub. I have read several of the threads on here about doing this and had read about the infamous hump. I was leery of what I would find when I pulled it out. I was pleasantly surprised to find that there is no hump.

http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zps36a0474f.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zps36a0474f.jpg.html)


There is only about a 1/2" lip there from the carpet to the fiberglass. And it looks like the hole that the ballast hose passes through is far enough back to not create any problems. The facade that the sub is mounted to is a piece of 3/4" HDPE.

http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zps1b73b231.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zps1b73b231.jpg.html)



I think I can build an enclosure that will be 19.5"x16"x7" (inside dimensions) as shown by the tape and not have any issues with anything behind the facade and not have to move it forward either.
http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zpscc069a26.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zpscc069a26.jpg.html)
We use HDPE at my business and I'm thinking I'll just use that to make the rest of the enclosure and just attach it to the existing facade. Is there any reason that I wouldn't want to do that? The sub measures 5" from the facade, is 7" enough depth? Also, the manual for the sub says I should have at least 1 cubic ft for the enclosure. This is bigger than that but I wasn't sure how much to subtract for the space the sub takes up?

[kaneboats]

Here's a good place to start:

http://www.bcae1.com/spboxnew2.htm

[MLA]

Glad to see you tackle this and enclose the sub. That is one very musical sub and deserves a good sealed enclosure and a proper tune.

@ 19.5 x 16 x 7 x .75 thick material, im coming up just over .8 net internal. In your calculations, did you factor in the material thickness?

Nothing wrong at all with the size you have for that woofer. It will be a little peaky and responsive. Adding a little poly-fill will soften it if you want to try some after the initial demo. Just make sure the enclosure seams are sealed, the enclosure's baffle wall is sealed to the facade and use a terminal cap or other, for the wires, not a drilled holes filled with silicone.

One you have the install, holla back and we can help with some tuning. Just need to know which amp you have.

[Jason05216]

My measurements were internal but yes I'm planning on 3/4" material

[MLA]

Gothya! out of habit, i took those as gross external. So in the neighborhood 1.25 internal is spot on IMO for that woofer. Converse to the above, if its a little mellow and you want to perk it up, add in some blocks to reduce the internal volume. It can be trial and error til you get the sound just like you want.

[Jason05216]

Any thoughts on using the HDPE for the enclosure.

[David Analog]

HDPE is fairly acoustically inert so that's a plus as compared to many other plastic products. But like MDF or other wood-based products, I wouldn't use less than 0.75" stock.
In addition to screws, you must have a glue bond for a completely sealed enclosure. Even with an aggressive thermal bond I've never trusted the seal long term of a plastic box. For that reason I prefer a wood product in one form or another.
In box building the execution is most important....even over the specific material used.
Coated & sealed, water-based MDF will last if executed correctly. Void-free Baltic birch is an upgrade as well as Medex, MDO, Norboard, or Extira, all solvent-adhesive-based products.
I would still seal any wood-based product.
Slightly elevating the enclosure off the sole to allow for drainage and evaporation is critical in all cases.

[Jason05216]

I'm planning to hold it up about 2". I planned to use 3/4" material. Could I use a gasket type material? Not sure what yet just thinking of something that might ensure that the joint is sealed tightly.

[David Analog]

A closed cell foam gasket could work if it was seamless, which is a lot of wasted material and not possible with a three-dimensional shape. If using HDPE, check in with the HDPE manufacturer for a thermal bonding product and then apply a silicon or other non-latex caulk to all interior seams. You might even course sand the interior edges that are going to be caulked. Nothing works as well as a precise fitting box with nearly perfect no-gap seams to begin with. Only then the bond has a chance to last.

[philwsailz]

One will have a hard time bonding HDPE... Precision will definitely be your friend. Still, you work with the stuff, so you probably know what adhesives will work?

I might recommend that butyl tape could be used as a sealant for the joints, provided you used a judiscious number, (lots) of screws to screw the panels together. The screws would hold the enclosure together and the captured butyl tape would provide the seal. If I were forced to build an HDPE enclosure that is probably how I would do it.

Here is a link to a page dedicated to bonsing HDPE panels together. Good luck!

http://www.eplastics.com/Polyethylene-Adhesives-Glue


Phil
Kicker

[Jason05216]

For the applications that we use it for we aren't concerned about the joints being airtight. We actually take the stuff apart at night to clean and sanitize it. It's in a meat processing plant that mostly produces snack foods. In our world we have to be able to clean stuff completely and crevices are a bad thing so we build things to be taken apart at the end of the day.

Maybe this isn't the best material for this application. I was just thinking since the piece that the sub is mounted to is HDPE I would use that and then I wouldn't have to worry about moisture.

[MLA]

With the right adhesive, I see no issue with using the HDPE.

[cornrickey]

I have yet to find applicable adhesive for HDPE.

[David Analog]

In this application, a woofer can create a surprising amount of internal pressure so a permanent airtight box is essential.
It really needs to be a thermal bond which is the same as welding the materials together with the same material.
Plastics and polymers are great in boats but I would go away from HDPE specifically on a boat sub enclosure.

[jmvotto]

So this fall I've been upgrading the stereo system that came in our '15 LSV. It came with Kicker amp that is driving 6 cabin speakers and a 10" Kicker sub under the helm. I added an Exile 15.4 amp and a pair of XM9's to the tower. I also added a ZLD while I was doing the other stuff. That all went pretty smoothly other than getting the speaker wire through the tower. That was a PITA. Thanks to Brian at Exile for hooking me up with the equipment and getting me the deal on the ZLD even though I was a little early and for taking the time to help me and answer all my noob questions.

After getting everything installed and working with the amps I was able to isolate the sub and discovered just how bad it sounds. I would describe the sound as a buzz, not a buzz like something was wrong, just a bad sound. I adjusted the Kicker amp and was able to make it sound some better but still not good. The amp is just mounted on the facade under the helm. It's not in an enclosure and the area into the bow seat certainly isn't sealed . The facade doesn't go all the way to the top.

http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zpsbf8bd007.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zpsbf8bd007.jpg.html)

So I have decided that I'm going to enclose the sub. I have read several of the threads on here about doing this and had read about the infamous hump. I was leery of what I would find when I pulled it out. I was pleasantly surprised to find that there is no hump.

http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zps36a0474f.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zps36a0474f.jpg.html)


There is only about a 1/2" lip there from the carpet to the fiberglass. And it looks like the hole that the ballast hose passes through is far enough back to not create any problems. The facade that the sub is mounted to is a piece of 3/4" HDPE.

http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zps1b73b231.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zps1b73b231.jpg.html)



I think I can build an enclosure that will be 19.5"x16"x7" (inside dimensions) as shown by the tape and not have any issues with anything behind the facade and not have to move it forward either.
http://i1347.photobucket.com/albums/p719/jasonjpm/Mobile%20Uploads/image_zpscc069a26.jpg (http://s1347.photobucket.com/user/jasonjpm/media/Mobile%20Uploads/image_zpscc069a26.jpg.html)
We use HDPE at my business and I'm thinking I'll just use that to make the rest of the enclosure and just attach it to the existing facade. Is there any reason that I wouldn't want to do that? The sub measures 5" from the facade, is 7" enough depth? Also, the manual for the sub says I should have at least 1 cubic ft for the enclosure. This is bigger than that but I wasn't sure how much to subtract for the space the sub takes up?

You will Have to move this forward as the conduit for the cables steering cable etc are in the way. I designed my sealed box upside down wedge to get the most foot room.

[Jason05216]

I did some measuring and I think if I hold it up 2 inches from the floor that it will fit without interfering with any of that stuff. I plan to make a cardboard mock-up to confirm that it all fits as I think it will. I also could fudge a little bit if need be by bringing the left side forward a bit. It just attaches with those brackets. The other side would require a bit more work if I have to go that route. I would have to cut the fascia board to go around the cup holder. That would also mean I would have to change the enclosure shape. Not wanting to go that route if possible.