After testing the woofer carefully, the next step
is to find the needed volume for the woofer. For the prototyping
the program will look at QTS and VAS more
than any other driver parameters.
To begin, create a new enclosure resource and then
bring up the enclosure properties and put the driver into chamber
1. In detail, do:
1) Resource / New / Enclosure. Name it appropriately
(mine is Vifa Box).
2) Bring up Edit / Properties (Ctrl+E) or right mouse
button or menu.
3) Go to the Chamber 1 tab and click the Select...
button to pick your driver.
4) Go to the general tab and set the frequency range
to 10Hz to 500Hz (or so), which is appropriate for a woofer like
5) Click OK to close the properties dialog and begin
For a detailed discussion of sealed versus vented
enclosures check out the subwoofer
Before deciding on sealed versus vented I tried prototyping
both kinds of boxes. The sealed box Q can range from 0.5 to 1.3
for reasonable results. As the Q approaches .7 the response gets
flatter and flatter. Over 0.7 the response starts getting a small
hump at the resonance (which keeps moving up as the Q increases).
Use the Sealed Box dialog (Calculate / Sealed...)
and vary the Q and look at box size and the various curves. I tend
to prefer a Q of 0.7 which would imply a box size of .319 cu ft
(or 9 litres).