An on-axis speaker produces no level variation from its own directivity.

Evidence

A small speaker mounted at ear height. Figure 7.30 shows a simple full-range speaker mounted at ear height and orientated to cover the entire audience area. The loudspeaker sensitivity is 94 dB per watt at 1 m. As the entire audience is “on-axis” there will be no variation in level due to speaker direc­ tivity; therefore, at the positions shown, the levels will be as shown in Table 7.4. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2505

Categorization

• DEFINE: Introduces ‘sensitivity in dB per watt at 1 m’ and ‘on-axis’ as measurable speaker properties governing coverage.