: Designing headphones and speakers that sound "flat" to the human ear requires compensating for our varied frequency sensitivity.
The phon scale measures the "level" of loudness, while the sone scale measures the "magnitude" of loudness.
A common rule of thumb is that an increase of roughly corresponds to a doubling of perceived loudness, which is represented by a doubling of the value in sones . Applications in Science and Industry phon scale
The human ear is most sensitive to frequencies between 2,000 Hz and 5,000 Hz (the range of human speech). It is much less sensitive to very low bass frequencies or extremely high treble frequencies.
The phon is not measured directly; it is derived through psychophysical experiments. : Designing headphones and speakers that sound "flat"
Here is a detailed write-up on the phon scale.
The phon scale is directly linked to the , a graphical representation of the sound pressure level required for a listener to perceive a constant loudness across the frequency spectrum. Applications in Science and Industry The human ear
The phon scale has several important properties:
However, as you move away from 1,000 Hz to higher or lower pitches, the relationship between phons and decibels changes.