I asked the same question and got this from the designer via a friend,
"the 67000 has a new woofer which is much faster and more punchy. I also refined the HF crossover to make the system considerably smoother, it is a major improvement overall. There are no upgrade kits to convert the 66000 to a 67000."
Good listening
Peter
Peter
"the 67000 has a new woofer which is much faster and more punchy. I also refined the HF crossover to make the system considerably smoother, it is a major improvement overall. There are no upgrade kits to convert the 66000 to a 67000."
Good listening
Peter
Peter