How is loudness mesured?

Answer 1

Loudness can be measured by a sound pressure level meter.

Loudness is a subjective measure, which is often confused with objective measures of sound prtessure such as decibels or sound intensity. Filters such as A-weighting attempt to adjust sound measurements to correspond to loudness as perceived by the average human. However, as the perception of loudness varies from person to person it cannot be universally measured using any single metric. Loudness is also affected by parameters other than sound pressure, including frequency and duration. In acoustics volume is related to amplitude, sound pressure, and dynamics.

There is subjectivly perceived loudness (volume), objectively measured sound pressure (voltage), and theoretically calculated sound intensity (acoustic power).

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