Figure 18.3 (h) in the 3rd edition of my book "Sound Reproduction" shows 0, 30 and 60 deg curves for the AR-9, and it was very well behaved. It got high scores in double-blind listening tests and the anechoic curves show why: flattish on-axis response, uniform flattish off-axis behavior - both characteristics that were lacking in many (most?) loudspeakers of the time. The extended bass and optimized room coupling helped - this is shown in Figure 9.12 which includes in-room measurements. Chapter 18 in the book shows anechoic data on many other loudspeakers of the period; it is called "Fifty Years of Progress in Loudspeaker Design".\n\nThank you. I notice on the same page, figure 18.3 (e) there are curves for the old Yamaha NS-1000M which are even more impressive. Date is ca. 1974! I had heard the NS-1000 on a trip and was well impressed. I was not in the market as I had speakers I really liked, the old Kef 104. Yeah, I know, the off axis dispersion wasn't great between 1 and 3 kHz and it was kinky about placement.