Final answer:
Gain in decibels is preferred for sound measurement because it aligns with the human ear's exponential response to intensity, making sound levels easier to understand. Decibels measure physical intensity, while phons measure perceived loudness.
Step-by-step explanation:
Expressing gain in decibel units is desirable because the human hearing has an exponential response to sound intensity. The reason for using decibels (dB) to describe the loudness of sound is based on the fact that the perception of loudness by the human ear is more accurately described by the logarithm of the intensity of sound rather than the intensity directly. This is because the human ear can detect a wide range of intensities, from the softest sound a person can hear, at 0 dB, which is the threshold intensity of 10⁻¹² W/m², to the loudest tolerable sounds, far above that threshold. Decibel measurement reflects how our ears perceive changes in sound intensity due to this vast range, making the scale much more manageable and understandable.
Another unit, the phon, expresses loudness numerically as perceived by human ears and is equal to decibels at a frequency of 1000 Hz, but while phons measure perceived loudness, decibels measure physical intensity. This difference emphasizes that the decibel system aligns more closely with the ear's response to changing intensities, making it easier for people to understand and relate to sound levels.