What is the calculation to fig. what the Port Frequency is of a box?

I have a ported sub box i would like to no what the calculation is to figure out what the port is in hz is the box is 2.5sq.ft the port is 2.5*16.5*14.25

What is the calculation to fig. what the Port Frequency is of a box?
Port tube length calculations for round ports:



input = Radius of Port (R), tuning frequency in Hz (fb), Volume of the box in cubic inches (Vb), (L) will be the resulting length of tube.



L = (1.463 X 10^7 X R^2 / (fb^2) X Vb) - 1.463 X R





For square vents, where the area of the vent, V, is in square inches, and the peak volume displacement of the cone, D, is in cubic inches:



V %26gt;= 0.02032 * fb * D



To reduce port noise, round off any sharp edges.



or you can just use this http://www.ajdesigner.com/phpvent/subwoo...



A good read http://www.trueaudio.com/st_ventq.htm
Reply:I got about 48 Hz using your dimensions. The calculation is



Fb = .159 sqrt((A*(1.84x10^8))/(V*(L+.823*sqrt(A))...



A = Cross sectional area of port

V = Volume of box

L = Length of port



48Hz is very high for a tuning frequency. Having a high tuning frequency means that you will have an enclosure that is more for loudness or SPL. If you have too high a tuning frequency you can damage your sub(s).



Good Luck!!!