Sub and amp for the boat

[BlueWaffle]

Hey guys...I need to put a new sub in my boat. Either 2 10's or 1 12". Do not want a free air sub so I'm sure a shop will build a box and install. I know nothing when it comes to amps...can you help me pick a sub(or 2) and pair it with a decent amp. I'm not looking for top of the line but definitely not cheap. If pics/install locations are needed I can get some.

 

[BlueWaffle]

Could i use the bottom of this seat as a box?

 

[MossBack]

In my opinion I would have the speakers under the rear seat moved somewhere else and have a custom box made under there. The problem with a sub under the driver seat is the balance of music. It would be off sounding in the middle like that. I am a solid fan of anything Rockford Fosgate. The marine line flat out ROCKS! http://www.rockfordfosgate.com/products/series/marine-subwoofers

 

[BlueWaffle]

Well I could put it facing one of three ways...shooting forward, on the back of the seat shooting toward back, or on the face towards the middle???

 

[BlueWaffle]

Maybe in middle of back under rear seat?

 

[BlueWaffle]

Or somewhere over here. You can see an 8 under that is a real piece of ****...

 

[jdc753]

I really don't know much of anything with marine audio, but I can't see any problems with any of those posted locations for a subwoofer. The lower frequencies are harder for the ear to localize to a speaker, so this makes the placement of the sub(s) a little less critical as the speakers. A pair of subs under the rear seat seems like a great idea.

Generally a pair of 10's will out beat a single 12, so it you went with a pair of these

http://www.rockfordfosgate.com/products/details/m210s4

then power them off this amp, http://www.rockfordfosgate.com/products/details/m750-1d


subs being single 4ohm would be wired up to a 2ohm load to the amplifier which dishes out 500w @ 2ohm which matches the sum of each sub's 250w power handling.

Wish I could be of more help, but sadly no experience with marine specific gear or installs. Maybe some other big boat guys will chime in.

 

[BlueWaffle]

I was hoping you'd chime in. So under the rear seat is just storage space. Would I just use that as the "box" or would I need to build something to drop in?

Instead of that rear seat, what about putting them under that pass seat (third pic) facing towards the isle? If i stay away from free air subs, would I need to get the volume of area under those seats to size them accordingly right?

 

[jdc753]

Those subs will need a dedicated box in either location, easiest to build it out of MDF and then coat it in fiberglass, or I would just build the entire thing out of fiberglass just due to the water environment n all. MDF and water absolutely do not mix.


Those subs are looking for 0.75ft^3 per sub, or 1.5ft^3 for the pair. Looks like from those pics you easily have that space in both locations. I honestly I don't put a lot of weight into sound quality on a boat, I feel it is more about output when on the water, so with that I personally would put the subs in the most convenient spot you can use, which seems like under the passenger seat.

I am not sure of the construction of the seat or the piece underneath it, but in a best case scenario it looks like you could remove the seat cushions and then build a box inside the base using the panel facing the aisle as the face of the box. Then you could just carefully cut/trim back the padded vinyl face to make the opening for the subs then you won't even need to recover that panel.


For sizing the box, if you measure up the area you have to work with, then start checking some numbers on this page you should be able to get the dimensions you need for the box to be 1.5ft^3 http://www.rockfordfosgate.com/Support/rftech.aspx#boxwizard

 

[BlueWaffle]

One thing I'm having trouble understanding is how to pair ohm ratings between the speakers and amp?

 

[jdc753]

Ah, easiest tool for this is Rockfords wiring wizard, http://www.rockfordfosgate.com/Support/rftech.aspx#wiringwizard

select the coil configuration of the subwoofers (will be listed anywhere you are shopping) Single Voice Coil (SVC) or Dual Voice Coil (DVC) and then select the coil configuration 4Ohm, 2ohm, etc


Generally when running multiply subs and especially in a single box, it is easiest to wire them together, and also wiring them together (in series or parallel configuration) can make for a lower overall resistance allowing you to use a "smaller" amplifier. Basically to the amplifier the lower the resistance the more power it can produce.

So an amp that can produce 250w at 4ohm RMS, can produce 500w at 2ohm RMS or 1000w at 1ohm *If it is stable down to 1ohm* Essentially the output doubles as the resistance is cut in half.


Parallel configuration

Series configuration

 

[Blacknight]

I don't recommend putting a sub where you sit. I have a exile system in my supra and when my sub hits the hull ripples the water. My but would go numb real quick. Additionally the fiberglass will need to be reinforced so the screws holding the sub in place don't crack the fiberglass or strip out.

If you make a MDF box just rhino line it or coat it with a water resistant material. You could always make a custom seat mount and build it to be much sturdier and to the correct internal dimensions for proper sound reverberation and mount a seat on top of it.... How creative you want to get is up to your time or wallet. Just remember to enjoy it and measure twice & cut once

 

[alradco]

I had a little system done over the summer in our wakeboard boat. I did a solo 12 in a sealed box with about 700 watts rms and it sounded great. Mine was in the front compartment on the passenger side. Playing with the box put it in the driver foot area and that worked well too but I wanted to keep it out of the way. I'm no expert but just seems like for an open area like that you need more power than in a car truck for example. Also had 4 6x9 inside and some tower speakers. Was very pleased with the outcome.

Peter

 

[cowwboy]

I have done a few wake boat systems and have a healthy system in my boat currently.
It will have to have it's own enclosure and be sealed with a spray on bedliner or fiberglassed over. The idea of building it entirely out of fiberglass is good. But to build it thick enough would be quite costly and most stereo shops do extremly poor fiberglass jobs.
Being that it is an open enviroment makes it harder.
You normally gain about 3DB going with a ported enclosure over a sealed. But that also opens your driver and interrior of the box to moisture.
I run a ported Digital Designs which has a paper / composite cone. So it doesn't like water but it is garage kept and after 3 years hasn't given me any trouble. But it will do mid 120'sDB outside the boat with one 12.
I would look at how much airspace you can get by putting it under the back seat and in the port side seat base. How tall are the seat bases?
I do like the idea of replacing a seat base with the sub box.
Lots of choices, just depends on how loud and how much money you want to spend.

 

[BlueWaffle]

ok bringing this back up. time to get crackin.


I'm leaning towards having a custom ported box built to fit under the rear seat. for the sub, a fosgate P3 10 2 ohm 500watt RMS.

trying to find an amp to power it. I want to push as much power to it as possible...being out on the water in an open cockpit boats needs some serious power to push this sub. so do I need to find an amp that pushes 500 watt @ 2 ohm? just a single monoblock sub amp? possibly the Fosgate Prime R500X1D.

 

[HOOV3R]

 

[Cutting-Edge Diesel]

like!!!!

 

[jdc753]

ok bringing this back up. time to get crackin.


I'm leaning towards having a custom ported box built to fit under the rear seat. for the sub, a fosgate P3 10 2 ohm 500watt RMS.

trying to find an amp to power it. I want to push as much power to it as possible...being out on the water in an open cockpit boats needs some serious power to push this sub. so do I need to find an amp that pushes 500 watt @ 2 ohm? just a single monoblock sub amp? possibly the Fosgate Prime R500X1D.

This sub here? http://www.sonicelectronix.com/item_36280_Rockford-Fosgate-P3D2-10-Newest-Model.html


If so this is a dual voice coil sub with each coil at 2ohm. That means you will wire the coils together like below to drop the final load down to 1ohm

The amplifier you picked is only stable to 2ohm so it wouldn't work with that single sub, at least not at peak power output, you would have to wire the sub differently to be a 4ohm load and then the amp will only deliver 300w.

If you can find another amp for cheap that will be rated for 500w at 1ohm, or get that amp and switch the sub for a dual 4ohm version, http://www.sonicelectronix.com/item_34787_Rockford-Fosgate-P3D4-10-Newest-Model.html

 

[BlueWaffle]

All that crap is confusing...all I know is that I need max power to drive it hard enough for the open cockpit.

How should I choose between dual voice coil, 2 ohm, 4 ohm,etc. one better than the other? I'm told the p3 is a quality sub and it'll take 500 watts rms...so that's what I want to throw at it.

 

[JrStroker]

The P3s rock. I've got 2. There is no 'better' way. Just ways of wiring them up.

I've got 2 4ohms 12" subs wired down to 2ohms on a 1500 watt 1ohm stable amp. 500rms older P3 12" subs. But since they are wired at 2 ohms they only get ~1000-1100ish watts.

To get the most out of a sub/amp combo you need a 1 ohm set up. A sub that can be wired right to run at 1 ohm and a amp that's stable at 1 ohm.

Look up amp wireing guide and see how your amp can be wired up. And find an amp stable that that ohm load @ 500watts and you're good to go. Preferably a mono block amp too.

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