The 1.6 was introduced in 2002 and sold approximately 3000 pair in its 10 year run, about the same as the CS1.5 from 1993 to 2002. All 1.6 cabinets, drivers, final assembly and testing was done in Lexington. My #1611-12 pair have Lex crossovers with Axon caps on printed circuit boards. "Late-date"CS1.6s (probably after Jim's death in 2009) had crossovers from FST.
I have done considerable investigation with the 1.6. I find it to be quite strong in all respects. My upgrade work has centered on physical elements with electronics review to come later. I am quieting the baffle for surprising increases in delecacy, harmonic detail and spatiality (as also is shown even more-so in the 2.2).I credit this forum for inspiring this exploration -specifically the questions about the Vandersteen baffle-less approach and the comments about being "harsh, aggressive, shouty". In reconstructing the product time-line, I realized that I had effectively dropped out of design evaluation by the time of mid 90s 3.6 finalization; and I would have been the person to explore non-electronic causes of subtle distortions. So, I'm playing catch-up 25 years later. And the results are enlightening on many levels of product performance and life's deeper questions.