Got the subs and amp now need help on design - Page 2 - Home Theater Forum and Systems - HomeTheaterShack.com

Old 09-07-13, 12:42 AM Thread Starter
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Join Date: Jan 2013
Posts: 174
Ok got some numbers put together for the boxes
All measurements are based on external measurements using single layer 3/4 MDF EXCEPT front which will be double layer (1 1/2")
Sub recessed into first layer

Sub #1 (front sub)
15" deep x 17" high x 89 = approx 13.13 cu/f

Sub #2 (rear sub)
12" deep x 31 1/2" high x 60" = approx 13.12cu/f

Making boxes these sizes, how much bracing is recommended and what size of slot ports would be required?
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Old 09-07-13, 03:01 AM
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Re: Got the subs and amp now need help on design

Quote:
stilly wrote: View Post
Ok got some numbers put together for the boxes
All measurements are based on external measurements using single layer 3/4 MDF EXCEPT front which will be double layer (1 1/2")
Sub recessed into first layer

Sub #1 (front sub)
15" deep x 17" high x 89 = approx 13.13 cu/f

Sub #2 (rear sub)
12" deep x 31 1/2" high x 60" = approx 13.12cu/f

Making boxes these sizes, how much bracing is recommended and what size of slot ports would be required?
where is the slot going to be facing out of ? the 15 inch deep panel, the side etc?

with boxes that long you'll need a significant amount of bracing to keep those long panels from vibrating. my suggestion is a panel brace every 7-10 inches done the length of the sub... and maybe double up the front and back baffles since running dowel rods 5 feet long might be a bit of a pain.
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Old 09-07-13, 05:10 AM
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Mike

Join Date: Apr 2007
Posts: 19,397
Re: Got the subs and amp now need help on design

15" deep x 17" high x 89" wide with a double front baffle = 10 cu.ft. internal volume. Subtract 1 cu.ft. for displacements of bracing, port, and driver = 9 cu.ft. net volume.

12" deep x 31 1/2" high x 60" wide with a double front baffle = 9.9 cu.ft. internal volume. Subtract 1 cu.ft. for displacements of bracing, port, and driver = 8.9 cu.ft. net volume.

I would suggest dual ports for each cabinet, on the sides for ease of construction.
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Old 09-07-13, 08:26 AM Thread Starter
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Join Date: Jan 2013
Posts: 174
I am away from home today but will post some drawings of what I was thinking of doing when I get back

If I went with two slot ports coming out each end of the enclosures, how many cu/inches is required and at what length? So I can include that in my drawing
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Old 09-07-13, 01:53 PM
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Mike

Join Date: Apr 2007
Posts: 19,397
Re: Got the subs and amp now need help on design

For the 15" deep x 17" high x 89 wide sub - port internal measurements: 1.5" high x 12.75" wide x 25" long - one on each side of the cabinet.

For the 12" deep x 31 1/2" high x 60" wide sub - port internal measurements: 2" high x 9.75 wide x 26" long - one on each side of the cabinet.
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Old 09-07-13, 03:24 PM Thread Starter
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Join Date: Jan 2013
Posts: 174
Quote:
Mike P. wrote: View Post
For the 15" deep x 17" high x 89 wide sub - port internal measurements: 1.5" high x 12.75" wide x 25" long - one on each side of the cabinet.

For the 12" deep x 31 1/2" high x 60" wide sub - port internal measurements: 2" high x 9.75 wide x 26" long - one on each side of the cabinet.
Thanks. I will try and make up some drawings tonight when I get back into town if its not to late.

Exciting day!!!! In Calgary picking up my theater room seating and surround inwall speakers. Yippee!!
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Old 09-07-13, 08:23 PM
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Mike

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Posts: 19,397
Re: Got the subs and amp now need help on design

I had no idea you were "next door". Albertan, eh?
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Old 09-07-13, 11:58 PM Thread Starter
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Posts: 174
Quote:
Mike P. wrote: View Post
I had no idea you were "next door". Albertan, eh?
Yes I am. I seen you are from rider country. Small world
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Old 09-08-13, 11:16 PM Thread Starter
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Does it matter where the port is located inside the box. Going to do a slot port, one exiting each side of the box, but does it matter if its at the top, bottom or in the middle of the box?
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Old 09-09-13, 12:40 AM
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Mike

Join Date: Apr 2007
Posts: 19,397
Re: Got the subs and amp now need help on design

It doesn't matter where, most have them at the bottom. I should also mention that you will have a cabinet resonance issue due to the long cabinet width. That is easily dealt with by packing in 4 to 6 inches of compressed fiblre glass insilation on each end of the cabinet. Cheap Walmart pillows works just as well, a couple on each end will do.
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