Phons And Sones -

is twice as loud as 2 Sones (and four times as loud as 1 Sone). 0.5 Sones is half as loud as 1 Sone. The Phon-to-Sone Conversion

To convert Sones back to Phons (often useful in engineering calculations): phons and sones

The transition from Phons to Sones represents the evolution of acoustics from a purely physical science to a psychophysical one. The Phon accounts for the spectral discrimination of the ear, aligning frequency response with the human experience. The Sone accounts for the magnitude estimation, providing a linear scale where arithmetic operations (doubling, halving) correspond to subjective perception. is twice as loud as 2 Sones (and

A is a unit of loudness level .