Loudness is measured psycho-acoustically via magnitude estimation against a reference

Evidence

The classic task that is used to explore how changes in loudness are perceived for known sound pressure level alterations in dB involves subjects listening to sounds at different sound pressure levels for which they make loudness judgments. To achieve this in practice, some sort of measurement scale is required with which the listener can judge the loudness of stimuli. A commonly used method involves comparing the loudness of two stimuli, a fixed-level reference sound and the test sound. The fixed-level reference is given a numerical value, say 100, and the listener is asked to give a numerical value for the loudness of the test sound as compared to a value of 100 for the reference. Thus if the test tone is judged to be twice or half as loud as the reference tone, the value would be 200 or 50 respectively. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 651

A commonly used method involves comparing the loudness of two stimuli, a fixed-level reference sound and the test sound. The fixed-level reference is given a numerical value, say 100, and the listener is asked to give a numerical value for the loudness of the test sound as compared to a value of 100 for the reference. Thus if the test tone is judged to be twice or half as loud as the reference tone, the value would be 200 or 50 respectively. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 651

Categorization

• DEFINE: Explains the magnitude estimation method used to quantify subjective loudness.
• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 651
• XREF: connects to: Psychoacoustics quantifies physical sound signals into perceived auditory attributes — Almo Farina, Soundscape Ecology: Principles,…, 976