Page 265 - Master Handbook of Acoustics

2
FIGURE 12-18 Measurements of sound-absorption coefficients of a velvet material (19 oz/yd ) in
free space, and about 4 in and 8 in from a solid wall. Also indicated are the points at which
absorption will increase due to wall reflection. (Mankovsky.)

The absorption of the velour is greater when spaced from the wall, and the effect is greatest in the

250- to 1,000-Hz region. At 125 Hz, the 10- and 20-cm spacing adds practically nothing to the drape
absorption because at 125 Hz, the quarter wavelength spacing is 2.26 ft.

Carpet as Sound Absorber

Carpet commonly dominates the acoustical picture in many types of spaces. It is the one amenity the

owner often specifies in advance and the reason is more often comfort and appearance than acoustic.