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View Full Version : designing a sub woofer box



k12ug
07-01-2007, 08:05 PM
so when in the process of designing a sub woofer box, the sub calls for a random space requirement, i have heard the bigger the better, but is there a point where the box is to big, and if and how do you find the ,"sweet spot" on how much volume to use when building a sub woofer?

take for instance.

a FI BTL 18"
the specs says:
5-8cuft for a ported box

would it be found with the combination for tuning you have the box for?

PV Audio
07-01-2007, 11:04 PM
Generally speaking, those space guidelines are directly related to the amount of input power you're giving it. If you have a larger box with less power, you can expect to get similar output with a smaller box with more power. This is assuming that the speaker likes the larger box better anyway, but that isn't always the case. The point is, when you have a larger enclosure, it is easier for the speaker cone to become undamped, and by such, can reach mechanical failure quite easily. The guidelines state what size enclosure the woofer performs best in, but again, you need to consider what is already in place before you decide to pick a certain Vb. If you have 3kw to give to a 2kwrms speaker, choose one of the smaller sizes to help keep the cone linear. If you have 2kw for a 3kwrms speaker, try to make it more efficient with a larger box. I repeat, this does not always happen, and the space guidelines are just that: guidelines. If you still can't decide, go with one in the middle and see how you like it. if it is too peaky, try something larger. If it is too boomy, try something smaller. If it is crisp and loud, then you did it right. :)