Handy Charts

Conversion of Phons to Sones

Phons	Sones	Music Dynamics
120	256
110	128
100	64	fff
90	32	ff
80	16	f
70	8
60	4	p
50	2	pp
40	0.5	ppp
32	0.25
25	0.25
19	0.125
14	0.0625
11	0.03125
9	0.015625

The phon and sone are units of perceived loudness. The phon is proportional to signal intensity in dB, while the sone is linear with perceived sound. Therefore, the two scales are not proportional. According to the definition by Stanley Smith Stevens who proposed the phon as a unit of loudness in 1936, 1 sone is equivalent to the loudness of a signal at 40 phons, which is equivalent to the loudness of a 1 kHz tone at 40 dB SPL.