River Floating Speaker Box
So, I am planning on building a floating speaker/grill combo for floating down the river. I don't plan on spending too much as it is more of a fun project and I already have most everything I should need, but I just wanted some input on orientation/size and box material, and any other suggestions people may have or things I should consider. I have had a basic floating grill for the past few years that has worked great and wanted to spruce it up a bit.
Parts I have:
2 Alpine Type S 6x9
2 GRS 69AS-4 6x9
4 GRS 12SW-4 12" subwoofer
Douk Audio TPA3116 2.1 bluetooth amp
2 ExpertPower EXP12120 batteries
I got everything wired up in the garage free air and it all is working to my satisfaction. I am running both batteries in series to give the amp about 25 volts. I have both alpine 6x9's in series on the left channel and the two grs 6x9 on the right channel, so 8ohms per channel. I have the 4 subs wired in series/parallel to the sub output, so 4 ohm load.
I have been planning on building a 6 cubic foot C shaped box (with room for the grill in the middle), separate boxes for each 6x9, and a separate watertight container to house the batteries/amp.
Something like this just to give you an idea, not sure if the chambers are necessary.
Thought 1: I am planning on going sealed mostly to conserve space as the ported recommendation from parts express is 60% bigger (not to mention being able to make the box watertight), but I was wondering if anyone who has played with these subs before might recommend them ported, especially since power is limited.
Thought 2: Should I put multiple chambers in the sub box or does it not matter since they are 4 identical woofers?
Thought 3: Does orientation matter much in open air? I am assuming I will probably want to keep the 6x9's just facing out (one on each side and 2 on the front), but I was wondering if anyone had an opinion on doing the subs facing out as well directly below them or possibly downfiring.
Thought 4: Material. I obviously want to go as light as possible, from what I read plywood is lighter than mdf, so I was leaning towards that route. Will coat with duratex or something similar, but I plan on the entire box to be floating above the water, so it shouldn't have to deal with much other than splashes. What is the thinnest mdf/plywood you would go on a sub box (remembering they are only powered by a tiny amp with a claimed 100 watt output)