Threshold in quiet affects loudness mainly for faint sounds

Evidence

This influence of threshold in quiet becomes clear when the curves outlined in Fig. 8.17 are used. For large excitation level, L E , the same specific loudness is reached independent of the threshold in quiet. For lower levels, however, the influence of threshold in quiet becomes very strong as the excitation level approaches the level given as the parameter. This means that the influence of threshold in quiet is most prominent for relatively faint sounds. Another effect also becomes visible: the influence of threshold in quiet, which is often assumed to play an important role, is smaller than expected for medium and high levels. The reason for this is that the three octaves between 20 and 160 Hz, within which the threshold in quiet changes drastically when plotted as a function of frequency, are reduced to the relatively small value of only 1.5 Bark if plotted as a function of critical-band rate. Therefore, the influence of threshold in quiet is usually effective in everyday loudness calculation only at the left end of the loudness distribution. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1281

Categorization

• DEFINE: Explains why threshold in quiet, despite being large in frequency terms (three octaves), is compressed to only 1.5 Bark on the critical-band-rate scale — hence its small practical effect.
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1281
• XREF: connects to: The loudness function approaches a vertical asymptote at the 3 dB threshold in quiet; Near-threshold sounds may sound louder to impaired than to normal ears — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 845; Low-Q resonance detection thresholds are remarkably low, making tonal changes easily audible.

Broader Connections

• Near-threshold sounds may sound louder to impaired than to normal ears #corroborates (0.75) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 845