Thin Walled Speakers -Tonian, Musical Affairs, etc

Nice writeup. But back to my original question... how do they sound with rock music? A lot of speakers sound great with acoustic music or female vocals, but fall apart with denser music.

Opinions from people who have heard please.

I don't have an experience with the speakers that you mentioned, but I have Michael Green Audio free resonance speakers. They are not exactly thin walled, however they have no damping material in them only some tuning things.
They are not bad at all with rock, electronic music etc. but are much better with small scale acoustic music and vocals. Also, they really require tight control by an amp or they get loose. Very sensitive to the smallest changes anywhere in the system, that is good for tuning.
So..wouldn't be my choice for rock though they are quite dynamic with good bass for the 8" woofer.
Anyone owns Musical Affairs? I am interested too.

I have Tonian Classic 12's. I can assure you that the speaker does not turn the music to sonic mud when playing rock or orchestral works. You might not like the sound of PHY based speakers but it would not be because of its lack of detail or coherence. I consider these traits one of its strong points.

Light weight and less damping do not go together; the BBC "Thin Wall" design was based on designing a cabinet with a resonance at a less critical point and then damping that frequency. Not easy to do; requires skill in design and building. Can work very well if properly executed but simply making the cabinet thin and cutting down on the damping is likely to give a colored sound. I currently have 6 pairs of the "Thin Wall" construction as well as others of heavier construction. Actually my S 100s weigh around 80 lb. so thin wall does not mean light weight.

I am a long time Spendor guy. They rock with the best of them.