ACOUSTA-WALŪ SOUND ABSORPTION COEFFICIENTS
Complete tables of coefficients of the various materials that normally constitute
the interior finish of rooms may be found in the various books on architectural
acoustics. The following short list will be useful in making simple calculations
of the reverberation in rooms.
|
Materials
|
Coefficients
|
| |
125cps. |
250cps. |
500cps. |
1000cps. |
2000cps. |
4000cps. |
| 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 |
| Same, on 40 oz. hairfelt or foam rubber |
.08 |
.24 |
.57 |
.69 |
.71 |
.73 |
| Same, with impermeable latex backing on 40 oz. hairfelt or foam rubber
|
.08 |
.27 |
.39 |
.34 |
.48 |
.63 |
| Concrete block, coarse |
.36 |
.44 |
.31 |
.29 |
.39 |
.25 |
| Concrete block, painted |
.10 |
.05 |
.06 |
.07 |
.09 |
.08 |
| Fabrics |
| Light velour, 10 oz. per sq. yd., hung straight, in contact with wall
|
.03 |
.04 |
.11 |
.17 |
.24 |
.35 |
| Medium velour, 10 oz. per sq. yd., draped to half area |
.07 |
.31 |
.49 |
.75 |
.70 |
.60 |
| Heavy velour, 18 oz. per sq. yd., draped to half area |
.14 |
.35 |
.55 |
.72 |
.70 |
.65 |
| Floors |
| 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 |
| Large panes of heavy plate glass |
.18 |
.06 |
.04 |
.03 |
.02 |
.02 |
| Ordinary window glass |
.35 |
.25 |
.18 |
.12 |
.07 |
.04 |
| Gypsum board |
| 1/2" nailed to 2 x 4"s 16" o.c. |
.29 |
.10 |
.05 |
.04 |
.07 |
.09 |
| |
|
|
|
|
|
|
| Marble or glazed tile |
.01 |
.01 |
.01 |
.01 |
.02 |
.02 |
| |
|
|
|
|
|
|
| Openings |
| Stage, depending on furnishings |
.25 - .75
|
| Deep balcony, upholstered seats |
.50 - 1.00
|
| Grills, ventilating |
.15 - .50
|
| Plaster, gypsum or lime, smooth finish |
| on tile or brick |
.013 |
.015 |
.02 |
.03 |
.04 |
.05 |
| Plaster, gypsum or lime, rough finish |
| on lath |
.02 |
.03 |
.04 |
.05 |
.04 |
.03 |
| Same, with smooth finish |
.02 |
.02 |
.03 |
.04 |
.04 |
.03 |
| Plywood paneling |
| 3/8" thick |
.28 |
.22 |
.17 |
.09 |
.10 |
.11 |
| Water surface |
| as in a swimming pool |
.008 |
.008 |
.013 |
.015 |
.020 |
.025 |
| Air |
| sabins per 1000 cubic feet |
|
|
|
|
2.3 |
7.2 |
SOUND TRANSMISSION CLASS
Approximate Sound Transmission Class (STC) ratings for Trenwyth's ACOUSTA-WALŪ units as compared to ratings for other units are shown below.
| ACOUSTA-WALŪ Masonry Units |
|
Regular Lightweight CMU |
| 4" |
49 |
|
|
| 6" |
52 |
6" |
43 |
| 8" |
56 |
8" |
46 |
| 12" |
62 |
12" |
51 |
|
