Dale's Enclosure Build (update: More Pics Added)

[freestylin]

Sup dale got some questions... when determining the net volume do we subtract the subs displacement and the bracing we are gonna to use and what can I use for bracing ? also what are some other materials would you recommend that i would need? Thanks

[Dale]

hey man...

when calculating the net volume, yes you must subtract sub displacement, bracing and port displacement.

there are a couple of things you could use for bracing....all-thread rods (hardware store) or wood should work fine.

using a double baffle, for example could strengthen your box and reduce flexing substantially.

if you use a 'snaking' port (L-shaped), that also helps make the box sturdier.

but if you really want to go the extra mile, fiberglass along with resin will really do a number on that box. after that it could withstand the weight of an elephant.

i notice that flexing could increase when the air has trouble leaving the box. hence, if you make your box as aerodynamic as possible, you can and will

increase the velocity of the air leaving the box. as a result you have less flexing because the air is not stuck in the box for too long, pressing against the walls.

add 45-degree angle cuts where practical and make sure your port edges have been rounded over.

hope this info helps.

[freestylin]

for bracing displacement what would i subtract maybe like 3/4 mdf also when i was looking at specs VAS is the sub displacement correct. Also would i have to subtract the fiberglass and resin from the net volume. I have also read about using screws and predrilling so would i just drill a hole fill the hole with some thing to seal it (suggestions) and then put the screw in?? thanks in advance

[Dale]

you don't really have to employ surgical precision with this. if you need 5 cubes net and your port consumes 1.5 cubes by itself, then a box volume of 7 to 7.25 cubes will cover the displacements.

The worst that could happen is that your tuning will be a hair lower...you won't be able to tell the difference. all i'm saying is that trying to calculate the displacement of every screw is impractical. just use your discernment and you'll do a good job.

for example...for my 15" sub, i need 6 cubes net. my port was a little under 1.5 cubes displacement. my total box size was about 8.3 cubes and it sounds damn good. the extra .8 cubes went to my 45 degree angle cuts (they take more space) and bondo. that should give you an idea...hope this helps.

by the way...VAS is not the sub displacement. simply put, it's the volume of air that would exert the same force as the suspension of the sub, if it were to be compressed to one cube.

[freestylin]

I been going through the manual and can't seem to find the displacement for the L7 maybe I'm not looking at the right thing or is there another term for but i think with the measurements i'm going with it will be fine so I did some measuring on my truck today and came up with max dimension of 14-16 inchs height, 40-42 inches width, and 25-26in depth. so I went with 14.5in H 39W 25D(GROSS) and the net volume 7.49 Cubic Feet without the displacements so what you think of this? Too Big ??? or just right

well I used the Rockford Fosgate Box calculator for that now and also i was thinking about something would i subtract thickness(like .75 because i will use 3/4 mdf) of the wood from the gross volume and than calculate the net volume. if so the internal measurement would be 13.75 in H 36.25in W 24.25in D and the net vol would be 6.99 cubic feet. Let me know if I'm going in the right direction with this or not. Really man I would want to thank you for helping me out I really appreciate it.

[Dale]

I don't mind helping at all man. It's my pleasure...I know how frustrating it can be when you wanna learn something but don't know what to do next.

If I remember correctly, you are installing 2 Kicker L7 12" subs. I'm guessing you'll probably go with DVC 4ohm each. Well the displacement on each of these subs are 151 cubic inches. If you divide that by 1728, you get 0.087 cubic feet. So you see that's not much space at all. With both subs, they'll displace about 0.2 cubes.

Now, I think you're headed in the right direction in calculating your net trunk space....but I'll go over it again just to make sure. Let's use your max dimensions of 14" height, 40" width and 25" depth.

To get your NET volume you need to subtract 1.5" from each dimension....(that is 2 X .75" for the wood).

So we have something like this: (14" - 1.5") X (40" - 1.5") X (25" - 1.5") = 12.5" X 38.5" X 23.5" = 11309.375 cubic inches.

Then to convert to cubic feet: 11309.375 / 1728 = 6.54 cubic feet. NET volume.

That's not too big for 2 12s at all. I would give each sub 3 cubes (that's usually the max recommended space for a 12") and leave the rest for displacement. So that volume is perfect for 2 12s.

Remember that bigger boxes will make your output louder with lower bass extension. If it's excessively big, then you may start having muddy bass. So 3 cubes net per sub it great. Do it man.

I had a 12 inch sub in a 4 cube box....about 2.5 for the sub and the rest was in port and displacements (tuned to 28 hertz haha). None of my friends could believe it was a 12 playing.

[freestylin]

Alright I will go that...on to designing the box I will probably go with the basic L shape port to keep things somewhat simple and I will see what I can get out winISD. Thanks for helping me with the calculations also.

[Chode69]

i know im WAY late but very nice work on the box!!!

[Dale]

thanks man.....before i take it all apart i promise to post vidz

[freestylin]

I'm having trouble with winISD a little ight i will just tell you what i do so far. I pick the Kicker driver for the L7 than I put 2 driver and than type of box which of course i pick vented. Next I pick for the alignment bb4 super boom box click on box and input the 6.54 cubic ft (or i'm suppose to input the gross volume) and than I get stuck on the vent and have no idea what to do next.