The 100 dB sounds of 40 Hz and 3 kHz are equally loud, because the loudness expressed in decibels is the same.

Question

Quizplus · Accepted Answer

The perceived loudness of a sound not only depends on its intensity (decibels) but also on its frequency. Human hearing sensitivity varies with frequency, and sounds at 40 Hz and 3 kHz do not have the same perceived loudness even if their sound pressure levels are the same in decibels.

The 100 DB Sounds of 40 Hz and 3 KHz