Originally Posted by
Giskard
You may notice that the default loss value in WinISD is something like 7. Better JBL systems measure around 10 to 12. These particular 8.99 cubic foot boxes I built measured just over 14, so "typically" the effective volume with a loss of 7 would have ended up with a higher effective volume resulting in an even lower tuning frequency. Enclosures that measure total losses around 3 are considered junk. In other words, how well you build the box will also have an effect. Keep in mind that Vb can vary by up to 20% without detracting from performance whereas Fb can vary by up to only 10% without detracting from performance.