Ok, I'm completly lost on this one. I know I need to achieve 30 hz, and I need 4.0cuft of space. I'm told this is the formula you use to determine the port length, but what about the volume inside the port? This is insanely confusing.
Lv = (23562.5*Dv^2*Np/(Fb^2*Vb))-(k*Dv)
Dv = port diameter (cm) Fb = tuning frequency (Hz) Vb = net volume (litres) Lv = length of each port (cm) Np = number of ports k = end correction (normally 0.732)
Can any1 give me any insight? This is for a 15 inch RE SE sub.