@roberjerman, oh how I lusted for a pair of the 2000A's in 1971! Their only competition was the ESS Transtatic, which also used the same, great RTR ESL tweeters---three of them. I have a pair I found in 1982, though they haven't been hooked up in years. While the 2000A had a normal looking enclosure hiding it's unique guts, the Transtatic was a 42" tall structure, with overhanging top and bottom blocks of walnut-veneered MDF.
most advanced speaker in a rectangular wooden box?
As you move up the scale of ingenuity and price, speakers take on different, sometimes fantastic, shapes and are made out of different, sometimes exotic, materials. So what would you nominate as the most advanced design that still houses its drivers in an essentially rectangular box made of some kind of wood product?