Originally Posted by Dmac420sj
So I think I messed up! So last year I built a 1.7 cu.' trapazoid sealed box for my jl 12w6v3 pushed with a hd 750/1. It sounds ok.... But thought I'd get alot more out of it. Thinking I should have done a hull faced mount. Can anybody with expierence in the 2 applications give me pros and cons? Thanks.
You have the right subwoofer and the right amplifier driving it. But you do not have the correct enclosure. That is the starting point with your situation.
A rectangular enclosure with different side dimensions is to your advantage. An extremely elongated enclosure that is too far removed from square is not good. Beyond that, the exact shape is not critical, whether all corners are 90s or a wedge shape.
Your enclosure is too large. It should be closer to 1.0 cu.ft. net after driver displacement is removed in a sealed application.
Too large of an enclosure will give you deeper bass extension but in an area lower than most material and will sacrifice energy in the meat of the bass. A sealed enclosure that is too small sounds dead and lifeless. Too small sounds live but peaky with a single note character. Either extreme reduces power handling. There is an optimum middle ground.
So begin by building the right size enclosure with a 'Qtc' in the .8 (minmum) to .9 (maximum) range per JL Audio specs.
Then follow Grant's suggestion for experimenting with different locations. You can also do the inverse by resting the enclosure on the driver's seat and move your head around the boat, in different nooks, and hear different results.
If I saw the boat I could predict the results with certainty and without the test.
Using the boat boundaries for effectively loading the sub can make a big difference.
Bass-reflex requires a sizable increase in the enclosure but is the easiest +3 dB you'll ever gain.
Btw, it's an open boat so don't take all the gusto out of the bass by tuning it the same as you would in an enclosed cabin of a car, truck or SUV.