Listener perception depends on sound power, direct sound, and reflections by frequency band

Evidence

The first observation is that if one wishes to anticipate how this loudspeaker might sound in a room, it is necessary to pay attention to sound power at low frequencies—it is the highest curve in Figure 2.6(b). The direct sound is dominant at the highest frequencies for the same reason. In the middle frequencies, all three components contribute significantly, so all three need to be measured. The on-axis curve by itself is insufficient data. Full 360° data, appropriately processed, is important information. An energy sum of the measurements contributing to these curves yields an estimate of a steady-state room curve, shown moved upwards by 10 dB for clarity. — Toole, Floyd E, Sound reproduction- the acoustics and…, 184

Categorization

• DEFINE: Establishes the operative framework that the three sound components (direct, first reflections, total power) each dominate different frequency regions.
• XREF: Connects to the standing directive claim about small acts of decorum — here it’s the analogous insight that multiple partial measures, not one idealized curve, constitute fidelity to the listening experience.