replacing Dunlavy SC-IV's

Dunlavy and Thiel share some design philosophies and I believe John
Dunlavy has been quoted as saying that he would probably own Thiel if
he didn't make his own speakers. Seems like they should be on your
list.

I also replaced my Dunlavy 4s with the Avantgarde Duos and couldn't be happier, the Duos are a major commitment of time and energy to get them to sound their best, but when you do they are magic. The Duos are so much more spectacular than the 4s, but can be problematic and frustrating if not set up well.

I had the SC-IVs which I liked very much but I wanted more definition in the midrange so I started listening to a lot of speakers and read about other folks experiences. I went to a single driver system so I could take advantage of SET amplification and get away from the crossover issues. I bought a sub that was fast enough to keep with the single driver speakers. I ended with improved dynamics and increased definition in the midrange and bottom end. I am very happy. Single driver speakers may not be for everyone - everyone is searching after their own audio nirvana. But I would take a listen to different types of speakers - planars, electrostatics, larger Dunlavy's, horn, etc.. Find out what you think you are missing and see what the tradeoffs are with other speakers. If you are going to spend $15K, consider changes to your amp and preamp and cables.... as well as power and resonance control. Good luck and enjoy!