Page 269 - Master Handbook of Acoustics

characteristics (Harris, 1957). The coefficients in Fig. 12-21 and included in the appendix are plotted
for comparison with Figs. 12-19 and 12-20. Carpets vary widely, which can account for some of the
great variability that confronts any designer of acoustical systems.

FIGURE 12-21 Carpet absorption coefficients. (A) 1/8-in pile height. (B) 1/4-in pile height. (C)
3/16-in combined pile and foam. (D) 5/16-in combined pile and foam. Compare these graphs with
those of Figs. 12-19 and 12-20.

Sound Absorption by People

The people comprising a concert-hall audience account for a significant portion of the sound
absorption of the room—perhaps as much as 75% for a full house. It can also make an acoustical
difference whether one or several people are in a small monitoring room. The problem is how to rate