Page 84 - The Master Handbook Of Acoustics

59
THE EAR AND THE PERCEPTION OF SOUND

2,000

1,000

500 1 /3 Octave 1 /6 Octave
Bandwidth - Hz 200 Classical

100 Equivalent
rectangular
band (ERB)
50 ERB 6.23f 93.3f 28.52 Hz
2
f freq. in kHz
30
100 200 500 1k 2k 5k 10k
Center frequency - Hz

FIGURE 3-11
1
1
A comparison of bandwidths of ⁄3- and ⁄6-octave bands, critical bands of the ear, and
equivalent rectangular critical bands (ERB) calculated from the above equation. 11

Loudness of Impulses

The examples discussed up to this point have been concerned with
steady-state tones and noise. How does the ear respond to transients of
short duration? This is important because music and speech are essen-
tially made up of transients. To focus attention on this aspect of speech
and music, play some tapes backward. The initial transients now
appear at the ends of syllables and musical notes and stand out promi-
nently. These transients justify a few words on the ear’s response to
short-lived sounds.
A 1,000-Hz tone sounds like 1,000 Hz in a 1-second tone burst, but
an extremely short burst sounds like a click. The duration of such a