what port length for 35Hz?

[oldschoolboomer 10+ year member]

built 23.9 gross square foot "wall" yesterday. the port dimensions are 5.25 x 50.5 x ?????. I need to know how long to make the port for @35Hz tuning. Maximum length is 19.25 which I believe would tune to @29Hz which may be a bit low for se15's. Need help asap as I want to get the port in and start the bracing and finishing work today.

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[oldschoolboomer 10+ year member]

bump

 

[azimuth 5,000+ posts]

can you widen it a little? or is that not an option. say 7 x 50.5? then it would be around 16 inches and box volume would be around 22 cubes. i'm assuming you made a mistake by saying 23.9 square feet. it's 23.9 cubic feet? correct?

 

[oldschoolboomer 10+ year member]

meant cubic feet. The port is only 5.25 tall due to space constraints. The overall dimensions of the box are:

24.5" deep x 37" tall x 52" wide. This is for 6 se15's.

 

[azimuth 5,000+ posts]

meant cubic feet. The port is only 5.25 tall due to space constraints. The overall dimensions of the box are:24.5" deep x 37" tall x 52" wide. This is for 6 se15's.

well. my calculations are wrong then. what is the displacement for each woofer?

 

[oldschoolboomer 10+ year member]

.17

 

[oldschoolboomer 10+ year member]

bump

 

[azimuth 5,000+ posts]

13 inches. you'll end up with about 21.5 cubes tuned in the mid 30's

 

[oldschoolboomer 10+ year member]

thanks a bunch. I have now finished all the bracing south of the port. 13 it is.

 

[jdawg 5,000+ posts]

bracing take up airspace depending on what you use for braces

 

[azimuth 5,000+ posts]

bracing take up airspace depending on what you use for braces

agreed. box size will come down, and also mess up your tuning. especially if you use 2x4's. all thread won't take up as much.

 

[jdawg 5,000+ posts]

all thread i wouldnt even worry with, but if its dowels or 2x4s, especially 2x4s if he used a bunch then it could up tuned pretty high real fast

 

[oldschoolboomer 10+ year member]

I used 3/4" plywood cut 3" wide with 45's. I braced the crap out of it and maybe used the equivalent of 1 20" x 12" piece.

 

[oldschoolboomer 10+ year member]

well maybe a little more than that. but not much.

 

[Dutchie. 10+ year member]

The ideal port area is 12-16 in^2 per ft^3