Note
that increasing the frequency of a sound in equal steps will lead to perceived
increases in pitch that seem to grow smaller with each step. For example,
click on the sound frequencies below, and you'll see a more noticeable
difference between 200 Hz and 225 Hz than 400 Hz and 425 Hz.
200Hz
225Hz 250Hz 275Hz 300Hz 325Hz 350Hz 375Hz 400Hz 425Hz 450Hz 475Hz
Entire
Series
Humans generally
hear sound waves whose frequencies are between 20 and 20,000 Hz. Below
20 Hz, sounds are referred to as infrasonic, and above 20,000 Hz as ultrasonic.
infrasonic
(about 20 Hz) < human hearing < ultrasonic (about 20,000 Hz)
We
know a great deal about human hearing, but what about the hearing of large
whales? Currently, we do not have detailed audiograms for the larger,
baleen whales (note: we do have information on the hearing of smaller
porpoises and dolphins from research with captive animals). Instead,
we assume whales can hear the range of sounds they produce. The
figure above compares human vocalizations with the sounds baleen whales
are known to produce.
|