Fi Btl Sub Enclosure
07-24-2010, 05:20 PM
#1
0 Watt CAFz'r
Thread Starter
Join Date: Jul 2009
Posts: 38
Fi Btl Sub Enclosure
Hey guys i need some help, after buying a 15" fi btl dual 1ohm off a member here i didnt measure my trunk properly thinking the current box it is in would fit but it wont fit after i tried so that being said i need new measurement for this box i got 31"length by 18" height by 19" deep i need this ported and want this thing to bang so any suggestions it is gonna be hooked up to a kicker zx 2500.1 2ohm stable so please let me know your guys's suggestion
thanks
thanks
Last edited by piggie; 07-24-2010 at 05:30 PM.
07-24-2010, 06:06 PM
#2
Is the box that wouldn't fit 18h x 19d x 31w or is that what you're currently wanting to use?
In which direction(s) do you want the sub & port facing?
RE Enclosure Calculator
Both sub & port firing in the same direction, with 1" MDF and a 3.5" wide port, you approximately (it's kinda ****y) get:
37.97HZ
56 square inches of port area
3.885 cubes minus displacement (.21cf3) = 3.675. 56"/3.675cf3 = 15.23x square inches of port area per cubic foot, which is well within the recommended 12-16 square inches of port area per cubic foot and is within the NET recommended space (3-5cf3). That's a relatively loud & compact box that should be tuned right around your cars (what is it?) resonant frequency.
In which direction(s) do you want the sub & port facing?
RE Enclosure Calculator
Both sub & port firing in the same direction, with 1" MDF and a 3.5" wide port, you approximately (it's kinda ****y) get:
37.97HZ
56 square inches of port area
3.885 cubes minus displacement (.21cf3) = 3.675. 56"/3.675cf3 = 15.23x square inches of port area per cubic foot, which is well within the recommended 12-16 square inches of port area per cubic foot and is within the NET recommended space (3-5cf3). That's a relatively loud & compact box that should be tuned right around your cars (what is it?) resonant frequency.
07-24-2010, 09:32 PM
#5
lol that was kinda the easiest way to say it.
18h * 19d * 31w = 3.675 cubic feet after displacments (displacements being port and how much the sub takes up), tuned to 38hz, and has 15.23 square inches of port area. Acceptable is 3-5 cubic feet with 12-16 square inches of port area.
To find the square inches of port area per cubic foot you have to multiply the port width by its height and then divide it by how many cubic feet the sub actually see's, therefore 3.5" x 16" = 56" (of port area), then you take 56" and divide it by 3.675 cubic feet, which equals 15.23 square inches of port area per cubic foot.
... because you can't have too little or too much port area per every cubic foot of space. Every sub is different.
If you make that box, it'll be really loud, but it will be lacking the lows. It will surely have decent lows, but it won't **** like 38hz+. If you're driving a car, 38hz is around the frequency that is amplified because of resonance, so the difference between 38hz and less than 38hz will be large, resulting in a noticeable difference between high's & low's that makes it seem like the lows are lacking.
If that's your first sub than you bought one of the best subs you could for a first system.
Can you face it into the cabin with the seats folded down? If you do that while stuffing the edges around the box with blankets etc than you'll get a noticable gain in SPL, but only if the cabin and trunk are near completely seperated from eachothers air space, and more-so if they are blocked off by wood or fiberglass etc.
It's a good starting box, but it would perform better in something like 4-4.5 cubic feet with 14-16 square inches of port area per cubic foot. It would probably also have a lower tune, something around 34hz.
18h * 19d * 31w = 3.675 cubic feet after displacments (displacements being port and how much the sub takes up), tuned to 38hz, and has 15.23 square inches of port area. Acceptable is 3-5 cubic feet with 12-16 square inches of port area.
To find the square inches of port area per cubic foot you have to multiply the port width by its height and then divide it by how many cubic feet the sub actually see's, therefore 3.5" x 16" = 56" (of port area), then you take 56" and divide it by 3.675 cubic feet, which equals 15.23 square inches of port area per cubic foot.
... because you can't have too little or too much port area per every cubic foot of space. Every sub is different.
If you make that box, it'll be really loud, but it will be lacking the lows. It will surely have decent lows, but it won't **** like 38hz+. If you're driving a car, 38hz is around the frequency that is amplified because of resonance, so the difference between 38hz and less than 38hz will be large, resulting in a noticeable difference between high's & low's that makes it seem like the lows are lacking.
If that's your first sub than you bought one of the best subs you could for a first system.
Can you face it into the cabin with the seats folded down? If you do that while stuffing the edges around the box with blankets etc than you'll get a noticable gain in SPL, but only if the cabin and trunk are near completely seperated from eachothers air space, and more-so if they are blocked off by wood or fiberglass etc.
It's a good starting box, but it would perform better in something like 4-4.5 cubic feet with 14-16 square inches of port area per cubic foot. It would probably also have a lower tune, something around 34hz.
07-24-2010, 10:24 PM
#6
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Thread Starter
Join Date: Jul 2009
Posts: 38
Okay all see if i can make more room lol i can go deeper if that helps like 24" deep if it faces in the cabin but i faced my 2 kicker L5 s 12" in the cabin and it sounded like shyt so im not sure if ishould face the back or the front can i pay u to make me a box lol if so let me know how much
07-24-2010, 11:20 PM
#8
If you stuff the trunk with blankets, and around the cabin/trunk opening (if it doesn't fit as a square wall) than it'll be louder and sound better. If you make the box the entire width and height of the opening (if it's square or nearly square) than it'll act as a wall itself (which is ideal). I think your L5s sounded like shizzle facing forewards either because they were tuned high and facing them to the rear of the trunk increased the lows or they just plain suck for sound quality, maybe the port area was too little or high. The sub and port would be in the same direction. In either case you can just flip the box around if it doesn't suit. RE's calculator is screwy but a box with the following space & tune is approximately:
30.54 width
18 height
24 depth
1" MDF
4.5" wide port
= exactly 4.5 cubic feet after displacements with exactly 16 square inches of port per cube @ 35.18 HZ (doesn't get much better than exactly), which would be much better for daily bumpin'. The tuning would be a little lower because of an added 1" MDF on the face of the box (adding to the port length/lowering tune) for support.
Even though I've never made one, I think I can make you a beast of a box. How much money are you willing to spend (off the top of my head, $200)?
Using better calculators (sealed box calc & port length calc), it works out to (I'm not sure, I'll have to ask)....
31" width
18" height
23.65" (+1" baffle = 24.65") depth
4.5" wide port (*16" = 72" / 4.501 cf3 = 15.99 sq.in. per cube)
4.501 cubic feet to the sub @ 33.397 HZ
... the tuning might be 36.199 hz because I'm not sure if the calc wants the longer dimension as the height or width of the port. With the longer part (16") as the height of the port, the tuning is 36.199 hz.
That's your best bet for a box (the 33.397 hz tune).
30.54 width
18 height
24 depth
1" MDF
4.5" wide port
= exactly 4.5 cubic feet after displacements with exactly 16 square inches of port per cube @ 35.18 HZ (doesn't get much better than exactly), which would be much better for daily bumpin'. The tuning would be a little lower because of an added 1" MDF on the face of the box (adding to the port length/lowering tune) for support.
Even though I've never made one, I think I can make you a beast of a box. How much money are you willing to spend (off the top of my head, $200)?
Using better calculators (sealed box calc & port length calc), it works out to (I'm not sure, I'll have to ask)....
31" width
18" height
23.65" (+1" baffle = 24.65") depth
4.5" wide port (*16" = 72" / 4.501 cf3 = 15.99 sq.in. per cube)
4.501 cubic feet to the sub @ 33.397 HZ
... the tuning might be 36.199 hz because I'm not sure if the calc wants the longer dimension as the height or width of the port. With the longer part (16") as the height of the port, the tuning is 36.199 hz.
That's your best bet for a box (the 33.397 hz tune).
