I am trying to use WinISD (its free, eh) to design a bandpass box for a couple IDQ10 D2 V.2 subs. I have all the required parameters except Le and BL (Qts, Vas, Fs, Re, Xmax, Z, Qms, Qes, SPL, Pe, dia, Sd). Do these make any difference whatsoever in the design of the box, can I calculate them from the other parameters? BL - The magnetic strength of the motor structure. Le - Length of wire immersed in magnetic field, in meters. Doesn't look like it to me.

BL and Le are not needed to perform sealed and ported box calculations. You can leave them blank. For a sealed and vented box, you need Qts, VAS and FS to calculate the required volume (and for the vented box, the helmholtz resonator frequency). QTS (well qes) is partially determined by BL. Also, Le is a measure of the speakers voice coil inductance, and is measured in henries, it is NOT the length of the wire, BL is the magnetic field strength of the motor, but it is derived from multiplying "L" which is the length of wire by "B" the magnetic field strength. I think you got Le mixed up with "L"

www.jlaudio.com doesn't hurt to do it by hand....there's a port calculation formula, takes awhile but well...it's nice... winisd uses a more simple one i'm pretty sure... sizing....depends what you're tuning it to math ... www.jlaudio.com like i said materials, mdf, pvc, anything that can take the pressure basically