2.4.5 Loudness and sound intensity (power) | Owners Corporation Network

2.4.5 Loudness and sound intensity (power)

The sound intensity/power is the sound energy transferred per second in a specified direction from the noise source to the air. The relative loudness that we perceive is a subjective psychological phenomenon, not something that can be objectively measured. Most of us perceive one sound to be twice as loud as another one when they are about 10 dB apart; for instance, a 60-dB air conditioner will sound twice as loud as a 50-dB refrigerator. Yet that 10-dB difference represents a tenfold increase in intensity. A 70-dB dishwasher will sound about four times as loud as the 50-dB refrigerator, but in terms of acoustic intensity, the sound it makes is 100 times as powerful.

The potential for a sound to damage our hearing is proportional to its intensity, not its loudness level. That's why it's misleading to rely on our subjective perception of loudness as an indication of the risk to our hearing.

Percieved loudness mapped to decibels

Decibel Level

Sound Intensity (Power)

Perceived Loudness

50

1x

1x

60

10x

2x

70

100x

4x