I have some of the plans , but as yet never built them.
However I have heard the DR250`s and T39`s , they are , shall we say different on the design front , the plans are really good , usually running to 40 pages , loads of angles , the DR 250 is a real challenge to build.
Bill uses the Eminence drivers for most of his cabs , and controversially peizo tweeters , how ever these are usually in a melded array of up to 24 units.
Made to the plans, these cabs will last , and far as sound , well they do sound excellent , as with most bins , the more the merrier , I dare say some of the charts are a little biased.
The only problem being , that bill designs his cabs for a specific driver , now joe blogs comes along , builds the cab and plonks any old driver in , and complains it sounds rubbish , bit like taking a Class "D" 15" driver and putting it in a Funktion one cab , yea , it will work , but it wont sound right ( nothing against Class "D").
Hope this helps a bit.
Daryll
