No offense to Graham, but WinISD does not take into account room gain and a person's listening preferences. He also limits his designs to sealed, ported, and passive radiator whereas PWK includes horn, transmission line, and bandpass as well. Maybe PWK is just hype as the only testimonials I have seen are on his page, but it seems like he has a pretty good business laid out. Also, he doesn't charge $100 for his plans. His blueprints are $50 and if you want a graph of the predicted room response, he includes that too for an extra charge. Perhaps PWK designs might be beneficial to this forum. I think you have to have some patience though because I think he keeps pretty busy and the turn around time might be at least a couple of weeks. I submitted an assessment form today. I'll let everyone know how long it takes to hear a response.