Building Acoustics

Multilayer elements 289

0.1 0.2 0.3 0.5 1 2 3 5

Distance between studs (m)

0

5

10

15

20

'R

max

(dB)

1

2

3

5

10

Figure 8.10 Acoustic lining attached to the primary construction by infinitely stiff studs. The maximum
improvement in the sound reduction index is given as a function of c-c distance of studs. The parameter shown
on the curves is the critical frequency of the lining in kHz.

63 125 250 500 1000 2000 4000

Frequency (Hz)

0

10

20

30

40

50

60

70

80

Sound reduction index

R

and reduction

'

R

(dB)

87 mm brick (Poroton)

w/panel + wooden studs

w/panel + steel studs

dR - Predicted

Figure 8.11 Brick wall with lining. Sound reduction index and improvement by lining of 12 mm chipboard
directly attached to the wall. Measured data from Homb et al. (1983).