Page 259 - Master Handbook of Acoustics

FIGURE 12-13 Sonex contoured acoustical foam simulating anechoic wedges. This is an open-cell
type of foam.

The sound absorption coefficients of Sonex for thicknesses of 2, 3, and 4 in are shown in Fig. 12-
14 for mounting A (material directly on hard surface). The 2-in glass fiber of Fig. 12-10 is

considerably superior acoustically to the 2-in Sonex, but some factors should be considered in this
3
3
comparison: (1) The Type 703 has a density of 3 lb/ft while Sonex is 2 lb/ft . (2) In 2-in Sonex, the
wedge height and the average thickness is far less, while the 703 thickness prevails throughout. (3)
Comparing the two products is, in a sense, specious because the higher cost of Sonex is justified in
the minds of many by appearance and ease of mounting rather than straight acoustical considerations.