Sound absorption coefficients for various materials

The following table shows the sound absorption coefficients as a function of frequency for various materials commonly employed in construction:

Materials	Coefficients
	125Hz	250Hz	500Hz	1000Hz	2000Hz	4000Hz
Brick, unplastered	0.03	0.03	0.03	0.04	0.05	0.07
Brick, without plastering, painting	0.01	0.01	0.02	0.02	0.02	0.03
Lime and sand plaster	0.04	0.05	0.06	0.08	0.04	0.06
Plasterboard	0.29	0.10	0.05	0.04	0.07	0.09
Carpet on concrete	0.02	0.06	0.14	0.37	0.60	0.65
Porous lightweight concrete block	0.36	0.44	0.31	0.29	0.39	0.25
Painted concrete block	0.10	0.05	0.06	0.07	0.09	0.08
Concrete or terrazzo flooring	0.01	0.01	0.015	0.02	0.02	0.02
Marble tiles	0.01	0.01	0.01	0.01	0.02	0.02
Wood	0.15	0.11	0.10	0.07	0.06	0.07
Plywood panel thickness of 1 cm	0.28	0.22	0.17	0.09	0.10	0.11
Chipboard panel	0.47	0.52	0.50	0.55	0.58	0.63
Hardwood	0.04	0.04	0.07	0.06	0.06	0.07
Hardwood on concrete	0.04	0.04	0.07	0.06	0.06	0.07
On hardwood slats	0.20	0.15	0.12	0.10	0.10	0.07
Rubber carpet 0.5 cm thick	0.04	0.04	0.08	0.12	0.03	0.10
Curtain 475 g/m2	0.07	0.31	0.49	0.75	0.70	0.60
Polyurethane foam 35 mm (Fonac)	0.11	0.14	0.36	0.82	0.90	0.97
Polyurethane foam 50 mm (Fonac)	0.15	0.25	0.50	0.94	0.92	0.99
Polyurethane foam 75 mm (Fonac)	0.17	0.44	0.99	1.00	1.00	1.00
Polyurethane foam 35 mm (Sonex)	0.06	0.20	0.45	0.71	0.95	0.89
Polyurethane foam50 mm (Sonex)	0.07	0.32	0.72	0.88	0.97	1.00
Polyurethane foam 75 mm (Sonex)	0.13	0.53	0.90	1.00	1.00	1.00
Glass wool 14 kg/m3 and thickness 25 mm	0.15	0.25	0.40	0.50	0.65	0.70
Glass wool 14 kg/m3 and thickness 50 mm	0.25	0.45	0.70	0.80	0.85	0.85
Glass wool of 35 kg/m3 and 25 mm thick	0.20	0.40	0.80	0.90	1.00	1.00
Glass wool of 35 kg/m3 and 50 mm thick	0.30	0.75	1.00	1.00	1.00	1.00
Ordinary window glass	0.35	0.25	0.18	0.12	0.07	0.04
Brick wall plastered with gypsum	0.013	0.015	0.02	0.03	0.04	0.05
Swimming pool surface	0.008	0.008	0.013	0.15	0.020	0.25
Doors and windows opened	1.00	1.00	1.00	1.00	1.00	1.00