Author

Material

Sound Absorption Coefficient

Frequency (Hz)

Dance and Shield [103] , Vorländer [104]

Smooth unpainted concrete

0.01, 0.02, 0.05

125, 1000 and 4000 respectively

Vorländer [104]

Rough concrete

0.02, 0.03, 0.07

- Ditto -

Brick wall, stuccoed with rough finish

0.03, 0.04, 0.07

- Ditto -

Brickwork, with facing brick of dimensions 230 × 50 × 55 mm

0.04, 0.35, 0.36

- Ditto -

Thin plywood panelling

0.42, 0.08, 0.06

- Ditto -

Solid wooden door

0.14, 0.08, 0.10

- Ditto -

Tiuc et al. [105]

Sawdust and recycled Rubber granules

0.65

0.979

300 - 3150

2000

Tiuc et al. [100]

Sawdust with 30% polyurethane binder

0.1 - 0.89

450 - 1600

Tiuc et al. [102]

Composite material made of 50% Flexible Polyurethane Form and 50% fir sawdust

0.09 - 0.89

100 - 800

Kang et al. [101]

Rice hull-sawdust composite boards

0.2

0.4

0.40 - 0.55

500

1000

Above 1000