Sydwayz

iTrader: (1)

My box is made out of 3/4 inch plywood, coated with resin and then carpeted. I wouldn't want one built any other way.

hotjava66

My subs are free air JL's, so it isnt really a box per say. They are mounted under the back seat and use that airspace. Sound pretty good, I cant totally enclose it because it is all the storage space I have.

4bus

iTrader: (4)

Free air subs are great, but keep in mind they only work 100% if the air from the back of the sub is separated from the air on the front side of the sub. My friend had 2 jl free airs under his hinged back seat. They sounds ok, but I knew we could do better. He needed access under the seat, so I designed "lids" for both openings. I used southco cam lock fasteners for easy removal. And dens foam weatherstip to seal the lids. The result was the boat went from some bass, to pounding bass! He had to re-adjust his head unit to compensate because the music sounds too bassy

I still box free air subs, free air just means I don't have to worry about the box being too big, the long excursion VC (voice coil) can handle it. A sealed or ported enclosure sub will have better sound, but in a free air situation the sub will fail as the VC will over extend and ruin the speaker.

glassdave

iTrader: (1)

good point, guess i never thought of that. Would it work better with a higher ply / higher density like Luan 9 ply? I have always cringed with any type of cast wood product like mdf in the marine environment. I guess its a double edge sword of sorts, either sound quality or more durable box. I know mdf wouldnt stand a chance with the pounding i put my boat through

4bus

iTrader: (4)

Maybe, but the problem is solid wood has an inherent resonance that will wreck the flat frequency response of any traditional cone-type speaker. The slight sound absorbtion of the the mdf is perfect. You want to hear the speaker, not the box. Like the opposite of an acoustic guitar. A 6.5" speaker mounted in a guitar would sound terrible. My Klispch lascala speakers ($3k each when new) are mdf veneered in cherry. My Pinnacle towers are also MDF, I know cause the wifey some how knocked a corner off one

Keep in mind you can gusset the corners of the box with hardwood scraps, I get mine from the local Stickley furniture factory for free. I use clear silicone for "glue", SS wood screws, then smoot the silicone joint on the inside. If you are concerned about repairs or removal, the silicone makes it easy. For more permanent installations use a high qual constuction glue, SS screws, but also use small wooden dowels to drill and pin the walls together. If my box breaks, chances are you boat is broke as well

hotjava66

The board I have now is MDF but no resin/glass coating and wrapped with vinyl. It is already punky and coming loose. I knew it wasnt kosher when it was installed and planned to fix it myself later. Another thing to think about, the rest of the seat box/floor/supports are fiberglass coated marine plywood or balsa, so really the backerboard for the speakers shouldnt make a whole lot of difference at this point should it?

4bus

iTrader: (4)

I good solid enclosure is more important than anything. Material type is more tuning for sound than anything. You ever hear a bose wave radio? That is a great example of sound tuning, however they dont use mdf tho But they spend a lot of time a research tuning the enclosure, the end result is filling a room with full range sound from 4" speakers, with real bass I have played around with different port sizes in both ported and band pass enclosures, you would be surprised what a big deal just a couple of inches makes (no pun intended).

If I took two good subs, and built equal size boxes...one from ply and one from mdf you would hear the difference, no question. However, if you don't hear the mdf you will never know right?

What kind of subs are you using?

Are they free air, standard. Are you planing on a ported or sealed enclosure?

As I stated earlier, if someone demanded ply and I had to build the box I would make it a sealed enclosure, and fill the box with speaker poly. The poly (like pillow stuffing) acutally effective makes the box bigger as far as sound and air ar concerned. So you will want to make your box a few 10ths of a cubic ft smaller than the recommended for best sound. The poly will help cut down on the unwanted resonence created from solid woods. wrap the outside of all surfaces with dynamat (or roofing membrane if you are cheap ) and enjoy the sound of the speaker itself, not the virbration of the material.

That kid that drives by your house with the trunk rattling, he can't hear the trunk in the car....you will hear both sides plus the boat, that "trunk" noise will ruin your sound quality.

Perlmudder

x2 except vinyl. put blocks in the corners for extra strength and some rubber feet on it so the water passes right under it. 2 seasons of splashing and pounding and it still sounds great!

Audiofn

If you don't want MDF then you want woods of various densities. Creating your own lamination of wood can be a pain in the butt as well.

glassdave

iTrader: (1)

Hey 4bus how bout a product like Coosa or Penske board for an enclosure? It comes in several different densities. Wonder if you could tune an enclosure with this.

http://coosacomposites.com/