Hi Pete I failed to add in my last post that I personally haven't used the f206 and as such I am only commenting on its performance based on its published T/S parameters using WinISD bass reflex design software. I think that it would be wise for you to get in contact with someone who has extensive experience with that driver. Martin J. King runs a web-site called [Quarter-wave.com] which deals with his very successful MLTL software which many have used with the 206e. MLTL stands for Mass Loaded Transmission Line. You might want to consider giving a good look at this approach for your 206e drivers. In his gallery section you will see many examples of member built enclosures which you can click on the builders name and e-mail them some questions directly. One of the designs also shows the BSC (baffle-step correction circuit) I mentioned earlier. Martin and many of his group are regulars on this forum and the Fullrange Driver forum. You may get lucky enough to be able to copy a existing sucessful design. Have fun Ron Brady