Which of the T/S Parameters show wat kind of box to use?

[flakko]

i remember something being posted like this not too long ago and there is a certain T/S spec of a sub that lets you know if the sub will work optimally sealed or ported. Which one is it?

[JimJ]

Efficiency Bandwidth Product...

Fs/Qes

[flakko]

and, what are the numbers that determine?

[PowerNaudio]

EBP:
taking the driver free air resonance (Fs) and dividing it by the electrical Q (Qes). If the resulting number is around 50 or less, you are looking at a driver that is best suited to a sealed type box. If the EBP is between 50 and around 100 or more, the speaker will work best in a vented enclosure. Horn loaded designs will perform best with an EBP of 150 or even higher.

Sealed box (and sealed bandpass) woofers should have the following characteristics:


Qts => 0.40
Fs <= 35 Hz
Xmax => 4 mm

Vented or ported box (and ported bandpass) woofers should have the following characteristics:


Qts <= 0.40
Fs <= 45 Hz
Vas should be relatively low (less than 4 cubic feet unless enclosure size is not a factor).