Lew, I agree that an armtube's internal energy transmission properties can only affect energies which cross the headshell boundary into the arm, and the design and materials of the cartridge mount affect that transmission.
FWIW, the single-screw plate design seems to provide some effective coupling in Schroeder arms. For example, I've A/B'd the Model 2 with a carbon fiber tube vs. a pertinax one. (Pertinax is a composite of resin-bonded paper fibers, somewhat similar to a treated wood, though less dense and chaotic than the exotic hardwoods used in the Reference and Durand's arms).
Audible differences between those armtubes were readily apparent. Pertinax provided a lower sound floor and greater individuation of tones than carbon fiber, which is consistent with my blah-blah above. In this case at least, the one-screw cartridge/headshell plate passed sufficient energies so that the energy transmision properties of the armtube material itself made some audible differences. The cartridge/headshell connection of the Durand design is virtually identical, so one would expect similar behavior.
That said, there is a boundary so some energies will indeed be reflected back toward the cartridge, as occurs in every tonearm. My only point was that whatever energies *do* cross that boundary into the armtube will be more effectively dissipated by a material with a chaotic structure than an organized one.
FWIW, the single-screw plate design seems to provide some effective coupling in Schroeder arms. For example, I've A/B'd the Model 2 with a carbon fiber tube vs. a pertinax one. (Pertinax is a composite of resin-bonded paper fibers, somewhat similar to a treated wood, though less dense and chaotic than the exotic hardwoods used in the Reference and Durand's arms).
Audible differences between those armtubes were readily apparent. Pertinax provided a lower sound floor and greater individuation of tones than carbon fiber, which is consistent with my blah-blah above. In this case at least, the one-screw cartridge/headshell plate passed sufficient energies so that the energy transmision properties of the armtube material itself made some audible differences. The cartridge/headshell connection of the Durand design is virtually identical, so one would expect similar behavior.
That said, there is a boundary so some energies will indeed be reflected back toward the cartridge, as occurs in every tonearm. My only point was that whatever energies *do* cross that boundary into the armtube will be more effectively dissipated by a material with a chaotic structure than an organized one.