Ten-phon increments double loudness, mapping phon to sone by powers of two

Evidence

Because loudness level measured in phon corresponds to the sound pressure level of the equally loud I-kHz tone, the equal-loudness contours plotted in Fig. 8.1 can be marked - besides the loudness level in phon - also with the corresponding loudness. Because an increment of 10 phon corresponds to a doubling of loudness, an increment of 20 phon corresponds to an increment in loudness by a factor of 4. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1188

Categorization

• DEFINE: Crisp statement of the phon-to-sone conversion rule (10 phon equals a factor of 2 in sone), the conceptual bridge between the two loudness scales.