Loudness grows faster at low levels than Stevens’ power law predicts

Evidence

Referring back from Figure 4–3, we also must consider the change in the loudness growth function that occurs at low levels. We observe here that the loudness growth function has a steeper slope at low sound levels compared with the slope at the moderate levels. The dotted line on Figure 4–3 shows the predictions for Stevens’ power law, and we observe that for low levels, loudness growth is more rapid than growth at the higher stimulus levels and does not follow Stevens’ power law. It is now well established that the growth of loudness is more rapid at low levels than at moderate ones (Hellman & Zwislocki, 1961). — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 727

Categorization

• DEFINE: Clarifies the well-known exception to Stevens’ power law that students of loudness must know.
• corroborated: 2 independent passages support this claim — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 727
• XREF: connects to: Below 40 phon, loudness falls faster than the 10-phon-per-doubling rule predicts; Loudness grows as a power law of physical intensity so relative changes match — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1262; Perceived loudness grows nearly linearly with intensity until steepening near 90 dB SPL — Dijk, Pim van, Physiology, Psychoacoustics and…, 2626 (+2 more)

Broader Connections

• Loudness-growth slope increases with hearing-loss degree but resists exact prediction #qualifies (0.80)
• A tenfold intensity increase is perceived as only twice as loud #exemplifies (0.72) — Eric J. Heller, Why You Hear What You Hear- An…, 143