I heard the 803D's- and another in the Diamond line. The tweeter impressed me alot- but that is it. The rest of the spectrum was colored, and mid-fi in quality. Bob grost from Cerious says he has experimented with Diamond tweeters (the Accutons I believe) , and his opinion is that as good as they are, they never integrate well with the rest of the spectrum. (aside from being fragile) That is what I seemed to hear in the B&W's
I have never heard any other Diamond tweeters though.
I have never heard any other Diamond tweeters though.