Originally Posted by 2fast4thelaw

The Zenclosures are little shy on volume for a single sealed 12" sub much less a ported sub. You generally need 30 to 40 percent more volume for a ported enclosure. If you are dead set on the Zenclosure box and want a vented alignment you may have to resort to a single 10" driver.

I have attached a software program that I wrote for calculating sealed and vented alignments and also it will calculate the optimum vented enclosure based on the speaker parameters used.

You will need to find the Thiele Small Parameters of the speaker your are interested in using, they are not hard to find.

You need the following values:

FS
VAS in Cubic Feet (You may have to convert from Liters)
QES
QTS

Also type in the value you wish to use for "Volume of Enclosure" By default I have entered 1

The values will be output to:

FCB
QTC
F3
FRMAX

all of these values will tell you very important information about how the driver will respond. The program will explain the values.

If you have any questions just pm me.