Sub Woofer Box Design?

How do you tune a sub woofer box for a sub woofer?

• Some sub woofers ask for a specific tuned box or sub woofer box. This one sub woofer prefers to be at 37 Hz or something

• Answer:

  if your looking to build the box your self, here is the formula: Lv = [(14630000 x R^2) / (Fb^2 x Vb)] - 1.463 x R Lv = length of vent (port) Fb = desired frequency Vb = required box volume (in cubic INCHES) R = radius of port (for square or slot port R = sq. rt. Area/Pi) so lets say you have a 12" sub that calls for 1cu' and tuned to 37Hz (sometimes they will give you "and use a 4" port"...or something...) lets plug in the numbers: Lv = [(14630000 x 4) / (1369 x 1728)] - 1.463 x 2 Lv = (58520000 / 2412288) - 2.926 Lv = 24.26 - 2.926 Lv = 21.33....or 21.25 long as you can see the tuning (which comes from the length of the port) is directly porportional to the amount of port area and box volume. i rarely tune to the specs of the sub. i personally don't like subs tuned this high. the 37Hz is the optimal tuning for that sub...not the only freq. to tune to. (i usually do between 28 and 34.) if the specs don't specify the area of the port, a safe bet is to use 12-16sq" per 1cu' of air space. (one 4" round port will equal about 12sq") the sub does not determine the tuning freq....it all comes from the box. whatever sub you put in the box will be tuned to 37Hz...you can safely do this provided it called for the same specs. there is alot more that goes into building boxes, but this is enough to get you started. one more thing to keep in mind is that almost all pre-made boxes are going to be tuned really high...why they do this i don't know. this is why it is always better to get one made for your tuning preference and situation.