Vandersteen Audio 3A loudspeaker Sidebar 3: Measurements page 3
The horizontal response family of the Vandersteen 3A, with any on-axis response deviations subtracted out so that the on-axis response appears as flat, is shown in fig.6. That response notch at just below 1kHz deepens at extreme off-axis angles. The overall dispersion through the midrange and top end—making allowances for the small ripples caused by cabinet reflections—is otherwise excellent. The vertical-response family (fig.7) indicates that listeners are better off slightly below the optimum axis than they are above it. Translated, that means that it would be better to err on the side of a slightly too-great cabinet tilt-back than not enough.
Fig.6 Vandersteen 3A, horizontal response family at 50", normalized to response on optimal axis, from back to front: differences in response 90 degrees-5 degrees off-axis; reference response; differences in response 5 degrees-90 degrees off-axis.
Fig.7 Vandersteen 3A, vertical response family at 50", normalized to response on optimal axis 39" from the floor, from back to front: differences in response 30 degrees-5 degrees above optimal axis; reference response; differences in response 5 degrees-15 degrees below optimal axis.