aero port question

[malandrin4o8 10+ year member]

Im building a box for 1 15" kicker l7. Box is gonna be 3.4cubes with 2 home made 4" ports tuned at 33hz. After plugging in all parameters i get 2 16.36" 4" aero ports is this correct or?

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[ObTechAudio]

I get basically 15.5"

 

[Jeffdachef 5,000+ posts]

Im building a box for 1 15" kicker l7. Box is gonna be 3.4cubes with 2 home made 4" ports tuned at 33hz. After plugging in all parameters i get 2 16.36" 4" aero ports is this correct or?

Might wanna go bigger with the box man. They like 4 to 4.5 cubic feet.

Input it in torres box calculator (download it)

Also find out whats the minimum SQ inches of port area you need (can be a little less because of aeros but keep close)

Car Audio - PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES

 

[Seraphim38 10+ year member]

another online calculator that works well, since the link above doesn't work. This is the one I like to use.

Speaker Enclosure Volume Calculator

Confirmed; for 3.4 cubes you can use two 4" aero ports at 16.4 inches in length to get you to 33Hz. Note, this is only 25 cubic inches of port area and you would be better if that was 30 inches or more. One 6" diameter at 18 inches long would get you 28 cubic inches of port area at the same frequency. Three 4" ports or two 6" ports both put you into ports that are likely too long to be practical.

As described above, for low end extension/performance a larger box would be preferable, but then your issue with the port surface area becomes worse. But, on the good side, your port lengths will decrease for the same tuning.