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 |