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".