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Bronze Member Username: JtbPost Number: 39 Registered: Jun-04 | Does anybody know how to calculate how to build a box so it will be tuned to 28 hz? I am going to build a box for one IDMAX and I want it to be tuned to 28hz. Is there any website calculator that can tell me the dimensions? Also the recommened enclosure for a ported box is 1.8-2.5 ft. So if I want it to be louder with less power I would build it at 2.5 ft as opposed to 1.8, right? thanks. |
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Silver Member Username: Davids2004Houston, TX USA Post Number: 491 Registered: Jun-04 | Here you go this should help ya. |
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Bronze Member Username: JtbPost Number: 42 Registered: Jun-04 | Thanks but one question, does the 'port diameter' mean if it is a 10" or 12" or 15" ect slot? because I put in 12", but when I push calculate it gives me a huge number like 140" inch vent length. I also don't understand the question 'are you using a slotted port' or what exactly Vent Length means. The length of the whole box? |
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Silver Member Username: Davids2004Houston, TX USA Post Number: 496 Registered: Jun-04 | The port diameter means the diameter of the port. Usually the diameter will be like 3-4 inches. A slot port is just like a rectangular port rather than a round port. Vent length just means how the vent should be once you put in the width and how tall it will be. |
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Gold Member Username: Jonathan_fGA USA Post Number: 1097 Registered: May-04 | Vent length is what you're calculating. You need a better calculator than that, that takes no account for the displacement of the sub and doesn't show you the net volume(which is what you're looking for). Go here: http://www.bcae1.com/spboxnew2.htm It doesn't have a slot port option, so heres what you do. Decide how big you want the slot to be (say you want 12" high by 3" wide, which is really big, but I'm doing it for easy math, also hint: the bigger the slot, generally the more SPL you'll get and the least port noise) get the surface area of that (12x3, or 30 in^2) Divide that by 3.14 and this will convert it to the equivalent round port diameter. Enter this diameter in the round port section and now you have the length you're looking for, it's exactly the same, the port volume and net volume (also will be the same as if it were a slot port) of the enclosure will all be listed. Since it's a slot port, ignore the error message on the bottom saying the port is too long, this isn't an issue w/ a slot port. You're aiming for a 2.5 cu ft box NET, not gross, unless Image Dynamics specifies otherwise, which I doubt. You'll actually get more SPL by tuning higher (like around 35 hz), but will lose a little sound quality and low end extension. |