Ive been messing around with WinISD. I don't know what to enter for the Fb parameter that it needs. The help page at the site that I'm using say it it is the "tuning frequency of the box". What does that mean?
My understanding of WinISD is that it is supposed to calculate Fb for you. WinISD uses the "Flat" alignment, so the Fb will usually be slightly higher than the speakers resonant frequency (Fs). Win ISD will also calculate the diameter and length of the port in order to achieve the desired Fb. The tuning frequency of the box is basically the frequency at which the cab's venting comes into play. Say for example, your box is tuned to 50Hz, the speaker cone's movement will be at it's minimum at 50Hz, but will increase when fed frequencies below that. That's the short answer. What type of cab are you designing?
OK that clears things up. Thanks. Im thinking of putting a coaxial 15" in a compact cab ala bag end's s15x only cheaper.
Ahh yes, you're the guy who has been speaking to Bgavin about the PAS CX-1580C. Keep us posted as to how it's going. And let us know if you need any help.