Nine ply, cross laminating tension free and total acoustic resonance etc are characteristics that Sonor markets so there is a lot of what Sonor labels as Sonor in the China line of drums and it is of course all marketing hype.
There are no tension free shells but there could be shells with less tension and I am sure every drum company has the secret family formula for this.
The S Class Pro shell build I saw did not look different from the Chinese shells. I would say that it was the same shell that Sonor introduced a few years later as “full maple Force 3005”.
Sonor becoming more or less Mapex or vice versa sounds about right to me.
QC
Regarding what are German Sonor SHELL Characteristics. Honestly, the KHS really does'nt have any of them. All major mfg's that have been making shells for a LONG time have excellent shell producing ability.
What makes German Sonor so special?
1. The plies of wood come in a "stave" like fashion, which you will see if you look close on the inside or outside. There are "panels" that you will see. I confirmed this with Sonor that it was on all plies. NOT on Mapex/KHS drums.
2. Grain is done vertically which has been for decades. This is not by chance or accident. You probably know dw just "miraculously" discovered this and it touting as their own.
3. Shells are under-sized, meaning they are actually slightly less diameter than what is marked. Premier does this too (most underrated major mfg. IMO). I don't know who else. This creates a "timpani" type effect. NOT on Mapex/KHS drums.
4. A few others might utilize this, but I don't think it is as "specialized" because Sonor still uses ALOT of plies without the "glue" deadening the shell. Tama lessened their plies possibly for that reason, but,
Sonor uses something "special" in their "resin". This is not your old fashioned, just slap it on there, etc... drum glue. It is something else, and I confirmed this with Sonor. My guess as to why, is that it creates a bonding material WAY above the average hardness.