After saying that the original DQ-10 tweeter/supertweeter setup was fine, and it was, curiosity and opportunity has gotten the best of me. I had a pair of Morel MDT-10s sitting around for a delayed project. I made fiberboard baffles, mounted the Morels and installed them right above the mid domes where the 3/4" tweeters were, and disconnected the piezo supers. After some initial listening, I adjusted the tweeter pad down about 1/4 of the way. I've auditioned strings, voice, electronic music, rock and jazz, and I don't think that revelation is too strong a word. I had Morel MDT-40s in my transmission lines for years, but the MDT-10s are smooth, articulate and revealing beyond what I had expected, and integrate well with the mid-domes. Billie's Best, Billy Holiday recordings on Verve from 1945-1959 sounds like a reference recording. The imaging is solid with the same depth, and they haven't negatively affected that, for lack of a better term, rhythm, or pacing, of the original configuration. So now, the only original surviving drivers are the dome midranges, since I've swapped in the Morels, Dayton midwoofers, and 12" woofers. I can't get over how forgiving the crossover/driver integration has turned out. I'd like to get another stock pair of DQ-10s just to have around. An idle mind is the devil's workshop!

I love these tests. I wish I had the space for a second pair of DQ-10s as one would remain stock, the other a nice bed for modifications.

Keep up the great experiments!

I was intrigued by this thread, but upon searching, I found that those Morel drivers hae been discontinued, and are no longer available. Any suggestions?

I too am completely satisfied with the current tweeter/supertweeter combination in my DQ-10's, but if I can make them sound better, which I did with the use of the Dayton Audio upper bass replacements, why not give it a try?

I just did a pair of Wharfdales. I used MDT-30. That is the only tweeter I have ever used when I build speakers.
Larry

I would have used any high quality tweeter available if I hadn't had the Morels and felt compelled to or had to make the swap. The standard for drivers is so high, you really can't miss. I love the Vifa D27TG and the Morel line, but Seas, HiVi et al all have premium tweeters that I'm sure would work. Just adjust the tweeter pad for any efficiency differences to your listening taste. Remember, integration is the key to preserving the original characteristics. Is there a little guilt or rather anxiety about all of the changes? In a way, but some of these drivers weren't available in the 70s. And if you have a genuine driver failure, why not take a chance and use your own judgment? Wouldn't you love to interview Jon Dahlquist about his and Saul's decision tree? Good luck, all.

Gr research has some good tweeters. Danny Ritchie is a member. He has done some design work for Usher and a few others.