I just got a brand new Reg. Cab f-150. I have a JL500/1 and an Alpine Type-R from my old car. I want to put it in my truck. I have about a 30" width, 20" height, and 9.5" depth limit. I want to use 3/4 MDF like i did in my old car. Alpine suggests .75-1.75 cubic feet for a ported 12" Type-R. I think i can get the 1.75 back there. The depth is concerning me because the Type-R is 7.7 inches deep and there will only be about 1 inch left behind the woofer magnet to the wood. Is this a problem? I really need help with the port design. It needs to be on the top of the box so it can be up to 20 inches long. I would like to get 33-35 hz. Anyhelp is greatly appreciated. Thanks! James Lively
Replies (4)
cplkittle on 03/18/2008 19:17:23
30x20x9.5 = 5700 cu in = 3.3 cu ft.
subtract for 3/4" wood: 28.5x18.5x8= 4218 cu in = 2.44 (actual internal volume)
- Port displacement .094 cu ft. = 2.346
- sub displacement .071 cu ft. = 2.275
Port sizes: 1.5 x 6 x
7.25" long = 33 Hz
6.25" long = 35 Hz
As long as you have over an inch behind the sub you should be ok. If there is any way to make it 1/2" deeper, that would be better.
F150Monster on 03/18/2008 19:44:56
Thanks for the reply i remeasured and tried to do the math myself in an earlier post. Up there is pretty much what i want to do i was just wondering if you could check my work please. Thanks alot. Your equation in the articles was really helpful and i think i got my math right but i dont know.
cplkittle on 03/18/2008 20:30:51
I wrote those articles quite some time ago, and have learned a few things since then.. such as how to use winisd to calculate box size and port length GRIN
That is the old school hard core way of calculating box size and port lengths.
newB on 03/18/2008 20:36:14
<3<3<3<3 WinISD <3<3<3<3
-Drew
Replies (4)
cplkittle on 03/18/2008 19:17:23
30x20x9.5 = 5700 cu in = 3.3 cu ft.
subtract for 3/4" wood: 28.5x18.5x8= 4218 cu in = 2.44 (actual internal volume)
- Port displacement .094 cu ft. = 2.346
- sub displacement .071 cu ft. = 2.275
Port sizes: 1.5 x 6 x
7.25" long = 33 Hz
6.25" long = 35 Hz
As long as you have over an inch behind the sub you should be ok. If there is any way to make it 1/2" deeper, that would be better.
F150Monster on 03/18/2008 19:44:56
Thanks for the reply i remeasured and tried to do the math myself in an earlier post. Up there is pretty much what i want to do i was just wondering if you could check my work please. Thanks alot. Your equation in the articles was really helpful and i think i got my math right but i dont know.
cplkittle on 03/18/2008 20:30:51
I wrote those articles quite some time ago, and have learned a few things since then.. such as how to use winisd to calculate box size and port length GRIN
That is the old school hard core way of calculating box size and port lengths.
newB on 03/18/2008 20:36:14
<3<3<3<3 WinISD <3<3<3<3
-Drew
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