Oh, that's neat. In playing around with my speaker placement, trying to find what imaged best, they ended up nearly in the position recommended by Cardas.
To given credit where credit is due, the Cardas recommendations are based on the long known mathematic principle of the Fibonacci sequence and the "golden triangle".
Heaven help us if Cardas were to take credit for devising that!
Their marketing machine would run into overtime.
Angstrom put out a similar pamphlet on the arrangement decades ago.
Those dimensions are indeed hard to match given that they place the speakers a huge distance away from the walls. I've found the best imaging sound simply comes from trying to form the triangle and worry less about the immediate wall interactions & distances. Most people just don't have the space for such a placement.
Oddly enough, the best stereo image i have of the three main systems in our house is my office.
