And human perception of loudness is also non-linear. The increase necessary for a perceived doubling in loudness is frequency dependent, but at most frequencies it's higher than 6dB. At 1 KHz you need roughly 10dB increase for a perceived doubling. See:
This is true, but the ear measures sound pressure, not sound intensity. Sound pressure requires a 6dB increase to double. See:
https://en.wikipedia.org/wiki/Power,_root-power,_and_field_q...
And human perception of loudness is also non-linear. The increase necessary for a perceived doubling in loudness is frequency dependent, but at most frequencies it's higher than 6dB. At 1 KHz you need roughly 10dB increase for a perceived doubling. See:
https://en.wikipedia.org/wiki/Sone