@soix Thanks! I am a long-time Thiel fan. I fell in love with the CS 1.5 when I was in college, during the early 1990s. I bought a pair brand new and still have them!
The 1.6 was a big improvement on the 1.5 and, as you mentioned, the tweeter is a big part of that difference. Plus - what a beautiful cabinet design.
If I could soften the tweet on the 3.6, I would. I don’t mean that I would make it quieter, but just a bit less bright. This brightness isn’t always apparent, but if a recording has a lot of high frequency noise, like some rock recordings do, it gets really bright in a hurry.
But then, to listen to Muse’s Absolution CD is a delight. It’s very particular to the recording.