Everybody sitting in boat enjoying sq background music with 3 class d kickers or equivelent on a good fresh battery give ya about 1-2 hours of music . You can always throw a set of $100 jumper cables under one of the cabin seats for if you get carried away .and deplete 3 of your 4 batteries .

This system you are building or thinking about building is quite impressive but the sub..

.http://www.jlaudio.com/m10ib5-cg-wh-...-drivers-91780

Enclosure Specifications


Minimum Sealed Enclosure Volume 2.0 cu ft / 56.6 L (or larger)
Optimum Sealed Enclosure Volume 2.5 cu ft / 70.8 L ..........................
Infinite Baffle Use Yes


I can help but saying are you sure....Jl makes some of the best slim subs on the market why not







http://www.jlaudio.com/12tw3-d4-car-...-drivers-92185

Just a thought that orignal sub welll..maybe not...




Wall Thickness 0.75 in / 19 mm
Front Baffle Thickness 0.75 in / 19 mm
Volume (net int.) 0.80 cu ft / 22.7 L .................................................. .....
External Width (W) 21.25 in / 540 mm
External Height (H) 16 in / 406 mm
External Depth (D) 6.5 in / 165 mm
F3 37.99 Hz
Fc 46.97 Hz
Qtc 0.9426

yes three SD amps on one battery will not work, but they do not draw any more power than any other amp to produce the same decibels from the same speakers. Since they have more power you might be playing louder than if you had smaller amps but watt for watt the current draw is comparable. I agree the JL HD amps can be a problem because the current really starts to climb as battery voltage drops as they try to maintain the same output.

one SD6 puts out more power than two M600/6's. Way more power if you bridge it or run the channels at two ohms. I had 2 M600/6's and one M1400 in my boat, they would kill (11 volts) two group 24 batteries playing loud for 10 hours. I now have two SD6's and the M1400, my two batteries will still last the same amount of time unless I have the REV410's playing also. Honestly it is so much louder that I rarely play it at full volume like I used to with the previous setup. I also have a second house bank of two more group 24 batteries that I can connect if needed, so I always have enough juice to last me all day and into the night. My two group 27 start batteries only start the engines and run the bilge pumps, so if I managed to kill all four house batteries I can just start one engine or both and start charging back up.

The benefit would be exrended sub life if you have a lot of wet people climbing over the seat .and you wouldnt have to worry about someone stuffing a empty beer can into the fancy cast aluminum basket of your 600 dollar w7. But enclosures made to survive the marine enviroment are not easy to build .and a sealed $375 dollar slim sub thats majic for truck owners will need substantially more power to match and surpass a $75 dollar type e
you will get punchier bass sealed dollar for dollar but a properly done 100 dollar sub will suprise you .we did a transmission line box in a mastercraft that used all of the bench seat space plus about 3 cf under the dash .had one jl audio 10w- 0 which was thier pre taiwan cheapie 80$ sub and it would flat blow your mind .but it took.over a week to build that enclosure and mod the boat.
the only thing that makes sense to me on your current deal is they have the sub bridged to all amp channels or head unit outputs are running bridged 2 ohm loads to all those speakers .or series at 8 ohms .make sure all that is correct before you go throwing a gazillion dollars worth of stuff at it .if it was closer to the season i would say punt that amp overboard cram 3 real amps for your 9 speakers in the cubby behind the head or up ander the dash .daisy chain or use pass thrus.you could be seeing jesus before the sun goes down.
but you have a little time ..

The distribution block has two direct connect and 3 fused connections. I would connect the PS (power supply) to the other 1/0 port (there is a 4g reducer fitting). This leaves a 3rd fused connection for another amp. This connection will charge the battery and provide power. Charge flows though out the system. (limited conditions that don't really merit discussion).
Order extra fuses. Properly installed, they should not pop BUT my experience, these larger capacity Mini's are not stocked by average audio shops or you will pay though the nose for them.

Install the PS anywhere in the cabin you choose. It has a standard 3 prong outlet plug. Use a heavy 12/3 or 10/3 extension cord (possibly sold as "appliance grade" if you need longer or run 4ga from the mount to the block.
Given all the large gauge cuts that will be made, spend the $20 on a cable cutter. It is so much easier and cleaner than hacking through with standard wire cutters, these cable cutters will slice like butter.
http://www.homedepot.com/p/Wiss-9-1-...CSJW/205208788

I have tried to moderate my recommendations to not come off totally power hungry but honestly, I think with 6 well driven full range speakers and that large of cockpit, a 10" free air sub is going to be like running twin 350's in your boat. Subs are tricky and with your limited knowledge, I would HIGHLY recommend you spend the $$ on having a 12" enclosed sub at a minimum (two would be ideal) built. (it will be like 1-2 weekends of fuel, but you will likely spend MANY more hours listening to music than running) Yes, you will lose half the storage under the bench.
You don't need a "marine" sub. Select a sub with plastic center and rubber surround. With a sealed enclosure, nothing internal will be exposed so salt air is not a concern. These will also let you to drop ohm resistance and maximize amp potential. Kicker Comp VR or VX or Rockford P3 or T1 would be some alternative choices to JL's very spendy subs. Avoid foam surrounds or coated paper cones.

You will be money ahead going with the 800/8 or powering the cabin with a separate cheap amp if you don't spend much time down there. Dedicated sub amps give you more control of the sub and don't leave you with wasted channels (money) when you make changes or lose full range if the sub amp fails/gets hot.

^ I would generally agree on building a cabinet too except Fountains have very limited storage so (for me anyways) that is out of the question. Losing my rear seat storage would be catastrophic! I think in this application 4 of these under the rear seat (or as many as possible) is the way to go. http://www.jlaudio.com/m10ib5-sg-wh-...-drivers-91733. Since you have one sub already in the cockpit which I am assuming is centered under the rear seat (?) you may only be able to have three subs (one on each side of the existing sub).

Building a cabinet for the subs under the rear bench is a nonstarter. As big as the boat is, storage space is still very much lacking and I can't give up the space under the seat. The sub that's there is already tight. I also have a bunch of other rigging running through that space.

I hear what you guys are saying about the one sub not being enough and its very possible that you're right, but we're not "party cove" listeners. Our needs are pretty basic, we throw the hook down for a couple of hours and want to listen to tunes in a mostly casual way. We're not really going to be blasting the stereo. The current system is simply garbage and my goal was to replace it with some good quality gear that would give me a big upgrade on sound quality and some extra features. If the one sub doesn't blow me out of the boat, that is OK... If I really find it lacking, then I will get some more and replace one of the amps.. I'm sure I could find a use for it somewhere else if need be.

With the help of my buddy, we figured out the battery setup on my boat. Each of the three engines has it's own dedicated battery and some of the other loads are spread across those three batteries. IE: trim tabs, drive trim, seat rams, cockpit lights are tied to port battery switch, cabin power is tied to starboard, etc. They're all wired to a bus terminal that ties them all together for the "ALL" position on the switches. The "2" position on the switches are dead. So when you select "1", that is the dedicated battery for that engine and any other loads wired to it. When you select "ALL", that load group is accessing all three batteries.

So, I will need to add a house battery for the audio system. And again, as big as the boat is, the space for more batteries is very limited, so I'm only going to be able to add one. I'm going to use one of the existing leads on my battery charger for the house battery, but I'm also going charge the house battery off the center engine alternator with the proper relay.

Thank you everyone for all of your responses. It has been extremely helpful and I've learned a great deal on this thread, which was my goal...

It's all relevant to your needs...hell, with all of our advise you would certainly end up like this guy! http://www.powerboatlistings.com/view/24995 Just make sure when you are wiring or placing components you leave yourself an upgrade "path" in case changes are needed you won't have to rewire the whole damn thing. Post up some pics when you get it all installed please!

LOL... I've seen that boat before, I'm surprised it still floats. I wonder if the owner makes his passengers leave all of their metal objects on land before they board, so they don't get stuck to the sides. There's enough magnets in their to pull people's fillings out of their mouths.

I was going for something just a little tamer than that...

They say there's no substitue for displacement and he does have some displacement going there....