What's an easy way to check the Fb of a ported cabinet?

[atilsley]

So many calculators out there....but I'm trying to determine the Fb of a ported cabinet with the following dims:

Volume is 255 litres (9 cubic feet).

Existing slot port is 300mm x 60mm x 20mm deep. (12 inches x 2.4 inches x 0.8 inch).

What else do I need to determine the Fb....?

With thanks.

 

[Galu]

You need to go back to the days before T/S parameters.

Fb² = (2700A) divided by V(L + 0.96√A)

Where:

Fb = enclosure resonant frequency in Hz
A = area of vent or pipe in cubic inches
V = volume of cabinet in cubic feet
L = length of vent or pipe in inches

 

[Indiglo]

Download Boxsim from Visaton, it has a utility to calculate Fb from box and port dimensions.

From the toolbar - Extras > Dimensioning of port > Port Tab

 

[atilsley]

Good one, thanks guys....appreciated.

 

[Galu]

I wonder to what extent the value of Fb calculated using my old equation (courtesy of Gilbert Briggs) agrees with that obtained using Boxsim.

If you use both, please let me know.