Thank you for the answers to my many questions via email. I thought I would switch venues so perhaps others could also benifit. I have been surfing many websites relating to building speaker cabinets. A common feature of cabinets the size that i am proposing to build (pro four pi) have substantial bracing, and in some cases 1" mdf of two layers of 3/4" mdf are employed.

Are such measures necessary for the cabinets that you have designed?

Thanks again for all of your help.

Tom