JNDL level dependence unifies across frequency when scaled to loudness level

Evidence

This characteristic is almost independent of frequency if, instead of the sound pressure level, the level above threshold (or, even better, the loudness level) is used as the abscissa. In this case, the level dependence of JNDL at both low and high frequencies remains almost the same. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1043

Categorization

• XREF: Loudness-level rescaling removing frequency differences anticipates later chapters’ pitch and loudness models; ties into why loudness level�not SPL�is the perceptual currency.
• DEFINE: Shows why ‘loudness level’ rather than raw sound-pressure level is the orderable perceptual axis for detection thresholds.