Page 117 - Master Handbook of Acoustics

many high-frequency incidental noises produced. (C. G. Conn, Ltd.)

Auditory Area of Speech and Music

The frequency range and the dynamic range of speech, music, and other sounds place varying
demands on the human ear. Speech uses only a small portion of the ear’s auditory capability. The
portion of the auditory area used in speech is shown by the shaded area of Fig. 5-11. This area is
located centrally in the auditory range; neither extremely soft or extremely loud sounds nor sounds of
very low or very high frequency are present in common speech sounds. The speech area of Fig. 5-11
is derived from long time averages, and its boundaries should be fuzzy to represent the transient

excursions in level and frequency. The speech area, as represented, shows an average dynamic range
of about 42 dB. The 170- to 4,000-Hz frequency range covers about 4.5 octaves.

FIGURE 5-11 The portion of the auditory region utilized for speech sounds.

The music area shown in Fig. 5-12 is much greater than the speech area of Fig. 5-11. Music uses a
greater proportion of the auditory range of the ear. Its excursions in both level and frequency are