I am using WinISD beta to build a sealed angled box for a SVC 12" 4ohm Alumapro Alusonic. They calculate an ideal volume of 1.18. First, does the program already take into account the displacement of the driver. My understanding of this driver was that it would need about 1.0 cu ft, so 1.18 ideal does not sound far off. I would like to make the enclosure smaller and I have heard about using polyfill because it makes the enclosure perform as if it had a greater volume. I understand how much to use per cu ft. However, how do you know exactly how much larger it is making the enclosure? Assuming you will stuff it, do you make the enclosure for .9 cu ft or 1 cu ft or something in between? Also, does it matter which surface of the box the sub is mounted on?
The program does not know what the sub displacement is, so air volume is given as net. You can't calculate exactly what action polyfil will make in any enclosure. Tried and true material is
Acousta-Stuf for an increase in air volume of up to 30%. "There is no replacement for displacement" is also tried and true......so try to make the box as large as is warranted. The driver can be mounted on any vertical side of the enclosure.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.