Unsound - good question. I think that suspicion arises because in later years there was sourcing of parts and some production to China, raising related questions. My general comments are that Thiel products were extremely finished at introduction. Nonetheless over time there were some refinements and/or adjustments for differences between as-designed and as-implemented. A common factor was that drivers' resonance modes might average slightly different than the original prototypes, so small XO changes would compensate.
Final testing compared every speaker to a standard in an anechoic chamber, which is how various drifting, etc. was identified. As a general rule, quality and consistency improved through the model life, as experience taught its idiosyncrasies.
Final testing compared every speaker to a standard in an anechoic chamber, which is how various drifting, etc. was identified. As a general rule, quality and consistency improved through the model life, as experience taught its idiosyncrasies.