SOUND ABSORPTION COEFFICIENTS

Coefficients

Materials

125Hz

250Hz

500Hz

1000Hz

2000Hz

4000Hz

Brick – Unglazed .03 .03 .03 .04 .05 .07
Brick – Unglazed, Painted .01 .01 .02 .02 .02 .03
Carpet – Heavy, on Concrete .02 .06 .14 .37 .60 .65
Carpet – Heavy, on 40oz Hairfelt or Foam Rubber on Concrete .08 .24 .57 .69 .71 .73
Carpet – Heavy, with Impermeable Latex Backing on 40oz Hairfelt or Foam Rubber on Concrete .08 .27 .39 .34 .48 .63
Concrete Block – Light, Porous .36 .44 .31 .29 .39 .25
Concrete Block – Dense, Painted .10 .05 .06 .07 .09 .08
Gypsum Board – 1/2″, Nailed to 2×4, 16″ O.C. .29 .10 .05 .04 .07 .09
Marble or Glazed Tile .01 .01 .01 .01 .02 .02
Plaster – Gypsum, or Lime, Smooth Finish on Tile or Brick .013 .015 .02 .03 .04 .05
Plaster – Gypsum, or Lime, Rough Finish on Lath .14 .10 .06 .05 .04 .03
Plaster – Gypsum, or Lime, Smooth Finish on Lath .14 .10 .06 .04 .04 .03
Plywood Paneling – 3/8″ Thick .28 .22 .17 .09 .10 .11

Fabrics

125Hz

250Hz

500Hz

1000Hz

2000Hz

4000Hz

Light Velour – 10oz/sq yd, Hung Straight, in Contact with Wall .03 .04 .11 .17 .24 .35
Medium Velour – 14oz/sq yd, draped to half area .07 .31 .49 .75 .70 .60
Heavy Velour – 18-oz/sq yd, Draped to Half Area .14 .35 .55 .72 .70 .65

Floors

125Hz

250Hz

500Hz

1000Hz

2000Hz

4000Hz

Concrete or Terrazzo .01 .01 .015 .02 .02 .02
Linoleum – Asphalt, Rubber, or Cork Tile on Concrete .02 .03 .03 .03 .03 .02
Wood .15 .11 .10 .07 .06 .07
Wood Parquet in Asphalt on Concrete .04 .04 .07 .06 .06 .07

Glass

125Hz

250Hz

500Hz

1000Hz

2000Hz

4000Hz

Large Panes of Heavy Plate Glass .18 .06 .04 .03 .02 .02
Ordinary Window Glass .35 .25 .18 .12 .07 .04

Other

125Hz

250Hz

500Hz

1000Hz

2000Hz

4000Hz

Water Surface, e.g. Swimming Pool .008 .008 .013 0.15 .020 0.25
Air, Sabins per 1000 Cubic Feet .09 .20 .49 1.20 2.90 7.40
Open Doors and Windows 1.00 1.00 1.00 1.00 1.00 1.00
Values Below are Given in Sabins/sq ft of Seating Area or Per Unit

Absorption of Seats and Audience

125Hz

250Hz

500Hz

1000Hz

2000Hz

4000Hz

Values Below are in Sabins/sq ft of Seating Area or Per Unit
Chairs – Metal or Wood Seats, Each, Unoccupied .15 .19 .22 .39 .38 .30
People in a Room – Per Person
(Do not use for Auditorium Calculations)
2 3 4 5 5 4
Audience – Seated in Upholstered Seats, Per Square Foot of Floor Area
(Use for Auditorium Calculations)
.60 .74 .88 .96 .93 .85