6 cubic foot box, 35hz, if i add 4 pvc round ports, how long do they have to be?

On mobileinformationlabs website it calculates 15.5 inches, however if I increase the port diameter from 4 to 8 inches it says that now the length should be 68 inches. If I reduce the diameter to a 1in pipe which IMO would be completely ridiculous it says the vent length is only HALF AN INCH!? So basically this makes no sense to me whatsoever. How would a 1in diameter pipe half an inch long be what is needed to tune to 35hz? and yet when I make the diameter 8 in it says i need over 5 ft in length?  

2 Answers

  • 2 months ago
    Favorite Answer

    It depends on what you are tuning for: 1 wavelength(WL), 1/2 WL or quarter WL.

    What is the purpose.

  • Jim
    Lv 7
    2 months ago


    Tuning is strange! But you have to think in terms of sound resonance and wavelengths.

    And this is why soooo many enclosures sound bad, and Bose is typically excellent.

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