Sound gain vs cost?
I run a simple coated truck box to the starboard side of my engine box.
Atrend "Slammer" box has lasted 5 years with a pair of 15" Kicker L7s pounding away but toward the end of last year, the MDF gave up.
I considered going back with the same or possibly stepping up to their SPL box which would increase depth (height when downward firing in my install) by 6". Unfortunately those boxes must ship truck freight which adds $150-200 or go as part of a big order in which case the mfg pickup shipping. No shop in a 200 mile radius has that box in stock or needs to place an order any time soon. So my final cost for that premade box would be $400ish.
A second option is a box from Q-bomb with similar dimensions to Slammer which would be about $170. http://qpowerinc.com/qbomb.php Atrend site is down at the moment
Atrend Slammer - 40x17x16 - net vas 1.75/side
Atrend SPL - 40x17x24 - net vas 3.0/side
Q-bomb - 38x16.25x18 - net vas 1.75/side *common chamber port
Other option would be custom and total $400-450 with a coat of resin inside and out plus truck liner.
Decisions on custom are - round vs slot port?
Slot port width, 2" or gains by going 3" for example.
Material thickness - 3/4" would add 1/2" to face for added strength or 1" total build. 3/4" sheets run $30 while 1" runs $53 and I have to go 40 miles to purchase. Gross VAS decreases from 5.72 to 5.47 with 1" holding my overall dimensions at 44x17x21 w/ 4" legs. Is there enough extra overall rigidity gained by using 1" material for the extra $30 and loss of .15 cu ft each side?
Ideally, I would like to stay under 21" total height including support legs. Top opening of gunwale compartment is 24" so 21 gives 3" to reach in a pull out noodles, etc.
I could be persuaded higher if the feeling is sound would be SIGNIFICANTLY better adding another 4-5"
Would a dual slot port out the back yield significantly greater sound than loading off the floor given the extra fab work involved???
Other factors - Currently spl test 133.5-135 db w RF T1500.1 amp. The 1-2 competitions I might do annually weight things such that adding less than 3 db bass would be insignificant for sure. Competition is just a little extra ego, max loud fun on the water within budget is goal.
I hope/need a FULL interior redo in the next 1-2 years at which time the box would possibly not be used so longevity is not high on the priority list.
So, how much better might a custom dual chamber custom box at $450 be than prefab single port Q-bomb at $170?
1991 MariStar 240sc, 454, tower, WetSounds, Krypt and Rockford Fosgate