Loudspeaker off-axis response dominates in-room energy at the listening position.

Evidence

As a means of understanding which sounds from the loudspeaker contribute to this measurement, the early-reflections and sound power curves from the anechoic data set at the top have been superimposed. Obviously, it is the off-axis performance of the loudspeaker that is the dominant factor in determining the sound energy at the listening location and, in the several comparisons that have been done, the early-reflections curve has been a better fit than the sound power curve, which is excessively tilted. As noted in Figure 2.6(b) the on-axis curve is the dominant factor at very high frequencies, so both of the overlaid curves underestimate the steady-state room curves at high frequencies. More direct sound is needed in the prediction. As is expected, the standing waves in the room take control at low frequencies and the prediction fails. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1319

Categorization

• XREF: Reinforces the spinorama/measurement discussion in Chapter 2 — off-axis response as the key in-room determinant.