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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