The meaning of LOUDNESS is the attribute of a sound that determines the magnitude of the auditory sensation produced and that primarily depends on the amplitude of the sound wave involved.
In acoustics, loudness is the subjective perception of sound pressure. More formally, it is defined as the "attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud". [1] .
The loudness of sound as perceived by human ears is roughly proportional to the logarithm of sound intensity: when the intensity is very small, the sound is not audible; when it is too great, it becomes painful and dangerous to the ear.
What Is Loudness, Really? To understand loudness, we need to separate three closely related terms: volume, decibels (dB), and loudness itself. Volume is the general sense of how “strong” or “intense” a sound feels to the listener. It’s what you adjust with a knob or slider.
Loudness is the perceived “strength” of a sound on a scale from quiet to loud. It is a subjective measure that considers the sound intensity, frequency and duration of acoustic or electronically reproduced sounds.
Loudness is measured in terms of decibels (dB), a logarithmic unit of sound intensity. A typical conversation would correlate with 60 dB; a rock concert might check in at 120 dB.
Amplitude plays the dominant role in loudness perception. If a sound is played at 50 dB and then the same sound is played at 70 dB, our brains interpret the 70 dB sound as louder.
Loudness is not simply sound intensity! Sound loudness is a subjective term describing the strength of the ear's perception of a sound. It is intimately related to sound intensity but can by no means be considered identical to intensity.