James
Don't bother win WinISD it has accuracy problems. If all you want is bass then grab a copy of Unibox provided you have MS Excel. It comes preloaded with a large driver base.
LspCAD is IMO the best program around. Jack's correct, there is a .pdf manual with the Adire freeware copy. This is a good way to learn, but of course you can only model their drivers.
Also there is a LspCAD users group. http://groups.yahoo.com/group/lspcad-users/