Does sub size matter?

I was just wondering if there is a standard for boats? I seem to see mostly 10"&12"s. just wanted to know if any benefit to going to 15 or 18's?
Thanks
Shawn

Yes, with all things being equal, surface area does matter. But executing the install properly matters the most. Letting the intended install space dictate the enclosure volume, then choose the right sub for the allowable enclosure. Next choose the right amp for the setup.

If you have 8 in-boats running with 150W rms ea, then a 10" sub with 150W wont cut it in balancing out the in-boat system. On the flip side, unless you are a bass-head, then 1000W 12" along with 4 in-boats powered off the head-unit will not be very pleasing. So take your current or future in-boat system into account along with what your sub goals are.

Shawn,
It all depends on what you are looking for.
In a boat with two coaxials in the bow and only two coaxials in the cockpit, then I'll probably run a stout 10-inch sub. Otherwise, with too dominant of a sub you'll never be able to have a balanced sound and the bass will be particularly boomy....unless you de-tuned the sub and nullified the advantages of a bigger sub. If you want sound quality you cannot overrun the coaxials. Now that is IF sound quality is an important objective. That's not always the case which is okay.
If you have six or eight 6.5" coaxials or 7.7" coaxials/components then you have the midbass power to integrate with a much larger sub and still maintain the proper relationship between bass fundamentals and bass harmonics.
Certainly more surface area relates to more output...at least peak output. But that doesn't necessarily translate across the entire bandwidth. Past a certain point the enclosure will be far more instrumental in the deep bass extension over the size of sub.
Also, compromising the sub/enclosure location to facilitate a larger sub won't provide much benefit. For example, a much larger sub in the port locker may 'hit' and 'pound' but it is more likely to sound tonally indiscriminant as compared to a direct radiating sub under the open driver's helm console.
Don't overlook the enclosure. A well-damped and conservative bass-reflex enclosure can produce an extra 3 dB of output (equivalent to doubling the amplifier power) and provide 1/3rd octave deeper bass extension before reaching it's half power roll-off point as compared to a sealed enclosure. So, the absolute largest sub doesn't always win.
So start with the most optimum in-boat location for the sub enclosure. The available enclosure displacement will often dictate the correct size of sub driver as well as the best loading method.
Enclosures for 15s and 18s are B.I.G. It's counter-productive to go with a larger woofer in a compromised enclosure.
That is a few of the bassics.

David
Earmark Marine

Thanks for the info. Right now I will just have factory 6 in boat. Plus a Roswell tower bar with lights i will install if I can ever get the right inserts..ha. I was just curious why never heard about 15's or 18's I know when I was younger it was all about having 2-4 15's or 18's but that was in cars. I know tmhe boats are differnt. I did find a powered box with a 12" and 500 watts ink it was wetsound but not sure would that compliment what I will have?
Thanks
Shawn

Shawn - you can for sure get into a 15 and have amazing results given proper power etc. But the reality is its boat dependent. In the Moomba line I see a lot of 12" woofers going into the outbacks, LSV etc. Stepping up into the XLV, I've seen guys successfully get into a 15. In the Supra's the helms have a lot of space and many guys have gone the 15 route.

There really is no right or wrong way to answer this question, other than to suggest you carefully look at the space your willing to give up to achieve a successful fit. I'd also make sure the rest of your system is up to snuff if you drop a 15 into play. Often times a 15" woofer can end up dominating the entire stereo.

Most will opt for a 12.
Some will opt for the factory 10.
And others will ask, "Do I need a sub at all...."

FIT FIT FIT. thats the key.

-Brian
Exile Audio

Vd matters more than just cone size. You could have a 12" subs with 2 mm Xmax and a 10" sub with 15mm Xmax and the 10 would destroy.