DD9515 enclosure 4 Cubes net + 2 6" aeroport questions

[Ronny 10+ year member]

I have read that when using multiple ports one must extend the length of both of them to reach proper tuning. I am hoping to keep right around 40hz tuning frequency. Can someone explain, or even calculate for me if it is easy enough, the length that both ports need to be? The box specs are 4 cubes after sub and port displacement in a trapezoidal enclosure. Also, with the aero ports from parts-express, you calculate the total port length needed, then subtract 3" from the center tube, cut it, and add the flares correct? Then the total length of the tube and flares when assembled will be one inch longer than the total length needed to achieve the tuning frequency?

Thank you much,

Ron

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[JG903 10+ year member]

At full length, the 2 6" precision ports will give you a tuning of about 42 Hz.

If you want lower tuning than that, the ports need to be longer or a bigger box is necessary.

 

[Ronny 10+ year member]

Great, thank you for the heads up.