WinISD – Box Design Program
WinISD is a great program that uses a speakers T/S parameters to help you design the perfect box for your speakers. This works on any type of speaker that does not have a built-in enclosure, You just need to find the T/S specs for the speakers. The best part, it allows you to model, sealed, ported, bandpass and even passive radiator systems. In fact, it will recommend a box size and type based off the T/S specs. It really is a must have for speaker and subwoofer builders/ designers. If you are unsure of how to use the program or what the T/S specs are. I recommend you check out these video tutorials to begin with:
The entire playlist can be found here: WinISD Tutorials