Boat Stereo Help Please - 9 spkrs/1 amp?!

[boattunez]

Hi! My winter project is an upgrade to our boat stereo - yet another boat components/wiring question(!). Any and all help/advice GREATLY appreciated!
Here is what I have planned out (diagram is attached - I hope!):
1. Speakers - 8x Polk MMC650
2. Amp - 1 x JL e6450m
Planned to run a pair of parallel speakers on each of 4 channels (2 ohms) - 2 in bow, 4 in main open cabin, and 2 on swim platform, and bridge channels 5/6 for sub (4ohms).
I think speaker loads are ok for this amp, but what about the sub - am I underpowering it or will it be ok? I really don't want to run 2 subs or 2 amps if I don't have to.
Not planning to run anything off head unit but maybe I should(?). Probable head unit? - right now leaning towards the 2007 Sony Marine Stereo CDX-HS70MW. Others considered: Clarion CMD4A, JBL M32S, Aquatic AQ-CD-1, Jensen MSR4115. Primary factors: marine-rated/weather-proof, wired & wireless remotes, iPod ready/control thru head, sat ready, flexible aux inputs.
Any and all help/advice GREATLY appreciated! Thanks all!

[WET HULL]

That would be fine in a car, but the stress a stereo is under in a boat is rough on the amps. The JL amp can handle it, but you will start to overheat the amp under a long play period. You can try it, but add a fan blowing across the amp to move the heat away. If it stesses it to much add another amp in the same location and split the wiring so you dont have to run new wires. Take your listening habits into mind. If you like it loud that will not do the job. Those speakers are rated for 75 watts rms I believe. You would only be giving them around 34 watts. That boat has the room for some goodies so I would put more in if it was me. :D A set up like yours I would typically run 2-3 amps. Hope that helps.

[Mr. Naudio]

that amp is 2ohm stable, but it will heat up in a boat if you boat in havasu,
you could get lots more play time if you ran the 6.5s in series,the trade off would be in sound quality.
You may or may not hear the difference (dont know your ear)didnt catch what the sub was but
prob one 10 inch.not enough power for to much more than that
would use the cmd4 with a matrix to up the input voltage to the amp

[dumbandyoung]

go with two kicker 15"s in a sealed box and call it a day

[Dub C]

that amp is 2ohm stable, but it will heat up in a boat if you boat in havasu,
you could get lots more play time if you ran the 6.5s in series,the trade off would be in sound quality. Here the quality should actually be better but the quantity of sound will be less (quieter)You may or may not hear the difference (dont know your ear)didnt catch what the sub was but
prob one 10 inch.not enough power for to much more than that
would use the cmd4 with a matrix to up the input voltage to the amp
My notes on running in series in red.

[Mr. Naudio]

My notes on running in series in red.
this would prob be true if he was running an amp with big balls not so in this case.JL6450
he will have to turn his gains up much closer to the S/N ratio so the increased dampening factor prob wont help the sound

[thmper321]

Actually Naudio and Dub are both correct. Running the speakers in series will help sound quality because of the increased damping factor but with less output like Dub said. If someone was to turn the gain up on the amp to compensate then there could be a mismatch of output voltage from the head unit to input voltage that the amp wants to see, thus causing poor sound quality like Naudio said. The gain control is simply designed to match the voltages not as a volume control. The six channel JL amp is not the best when it comes to output.
You could get a monoblack for the sub and use the 6channel JL amp for the polk speakers.

[boattunez]

Thanks for inputs all! :D
After LOTS of analyzing/comparism (over-analyzing?) have decided to run the Clarion CMD4A head unit ... was tempted to get new Sony CDX-HS70WM (nice!) but went w/ CMD4A multiple remotes capability, Sirius-ready and fully integrated iPod interface ... plus silver face fits better w/ my finish than the Sony black ...
... also added a Clarion APX480M marine amp ... will run cabin spkrs and sub off JL 6ch ... and run bow and aft spkrs off the Clarion 4ch ...
... now looking for an on/off/fader/vol control to put between amps so I can fade 4ch amp bow vs aft/swim platform spkrs ... any ideas GREATLY appreciated ...
... also have to decide where to put amps ... leaning toward next to batteries in engine compartment - lotsa room, easy access, and figure amps should stay as dry & cool as batteries ...plus very short power runs vs longer RCA runs to head unit ...
... fun, fun, fun ... will be glad when weather gets above freezing here so I can start installing ... instead of planning !!! :idea:

[ROZ]

If I was building a loud sq car, I'd get a clean high output amp and run it 8ohm..
I want to thank Thumper for validating DubC and NAudio's posts :)