Lanceg

Hey guys....I'd like to install a new sub(s) and amp in my boat. I basically know nothing when it comes to pairing the up with a correct amp. I also need some help selecting sub placement. Would you suggest 2 10"s or 1 12" and the most important question is what amp to run with them.

For placement...I have a few options (I think). First and foremost, can I just utilize the existing space under these seats to basically turn it into a box or do I physically need to build a box and then place it in the correct spot? I'm not really interested in a free air sub so sealed or ported box will need to work.

First....in between the 6x9 under the back seat.



Second...under the drivers seat. I can face it forward toward the bow, to the middle, or to the rear. I'm assuming I just use the base of the seat as the actual box??



Third...pretty much the same as the last one but a larger box space because of the back to back seats??




For equipment, I'm not looking for top of the line like a JL W7 or anything but I don't want cheap either. I know the amp is the most important part so that's really where I need the best suggestions.

Thanks!!

BIGBREW

Boat stereo = Big amps if you want to be able to hear it. I have my amps mounted up in my cuddy. I have 1 1200 watt amp to run two 12 inch subs that are also up in the cuddy an I have a 500 watt that runs 4x6.5 inch speakers along the bottom of the back seat like where yours are.

Lanceg

Right...but 2 ohm, 4 ohm? Just look for total wattage?

ChargeIt

Since your sig is incomplete. Where/what kind of water do you boat? fresh or salt?
Primary listening - in the boat while crusing? in boat party? behind boat party? sand bar?

If you were to use a 12" where do you have the height to install?

Lanceg

Sorry...it's a 24 Ultra Stealth. Used on freshwater lakes in Texas. Music will be mostly listened to while cruising and floating. I'm leaning towards 2 10"s and putting them under the seat facing the isle (third pic) if people think its possible. If I stay away from free air subs, I assume I need to find volume of storage area under that seat to size properly??? From there, I really need help finding the right power to go with them. Are marine grade subs a definite requirement?

phragle

iTrader: (3)

Im still picking out subs, but Im putting together a system with 4 mtx 7.7 tm7702 coax's and a directed electronics 1200/5 amp. when 'sizing' you will pick up volume/power with lower ohms (good amps should be 2 ohm stable with a good sub amp 1 ohm stable) . with a stable amp general rule of thumb if that you have an amp that puts out 45 watts at 4 ohms it should be about double at 2 ohms. Now at first you may go woohooo and drop your ohms as low as possible, realize that at lower ohms your amp will be working harder and getting hotter. And it will suck more juice.

Think of it like your boat. You want to cruise at 70. you can put a motor in it that will push it 70 (say a 7.4 330) but is screaming its brains out. Its not going to be very trouble free or live long being maxed out all the time. So you can put a bigger motor in it that will push your boat 90 wot, (say a 525 eti) but at 70 its purring along happy and non stressed and will live a long happy life. At the same token you don't want to go to overboard. If you only have a bravo drive sticking a 1000 hp blower motor in it will let the motor live a nice life as it isn't coming close to breaking a sweat however your bravo is now in 1000 pieces.

So I have good (not excellent) components. My amp is a class a/b-d hybrid. a/b on the four channel rated at 2 ohm stable and I will be running 4 ohms fairly well matched to the speakers and my class d sub channel will be pushing 2 ohms even though its 1 ohm stable. I should be able to set the gains at a respectable level for good headroom while getting decent volume in my little resin bucket.

mptrimshop

So running 4 ohm will pull less juice and keep the amps cooler?

phragle

iTrader: (3)

Depending on the amp. if its 2 ohm stable yes. if its a 4 ohm amp you are maxing it. it you drop below the ohm rating of the amp you will cook it quickly.


Ohms are resitance, think about a prop. a 21 pitch prop has less resistance against the water than a 24. so your boat comes out of the hole easier with a 21 and the engine revs higher but if you stick a 14 pitch prop on it that's even less resistance but your going to spin the motor 10.000 rpm and grenade it. put a 30pitch prop on and even though your motor can push your boat 70 with the right prop, it is struggling against so much resitance that you actually loose speed.

nailit

He could also run the 6x9s in low pass!! I bought a box, modified it, cut the hole in my 25ol under bench then decided to set amp to low pass on 6x9s under bench.. then,.said...$hi$!!! Could have done that., I can tell you that 8" bazooka full range marine sound great!! Had 4 in my Larson.. holy crap!! Sounded good, but I had the room already!!

Lanceg

So how should I match ohm rating between amps and speakers? Do most good amps have multiple ohm outputs? So could I get an amp with 4 and 2 ohm outputs and put a couple 2ohm speakers on it?