TABLE I Values of reverberation time | |||||||||||||||||
Absorption at frequencies of | |||||||||||||||||
125 | c/s | 250 | c/s | 500 | c/s | 1000 | c/s | 2000 | c/s | 4000 | c/s | 8000 | c/s | ||||
Surface | Area Ft2 | Material | α | Total absorption | α | Total absorption | α | Total absorption | α | Total absorption | α | Total absorption | α | Total absorption | α | Total absorption | |
Hall Ceiling | 4800 | Concrete slab on trusses | 0.02 | 95 | 0.02 | 95 | 0.03 | 145 | 0.13 | 145 | 0.14 | 190 | 0.04 | 190 | 0.04 | 190 | |
Hall Floor | 4800 | Concrete Floor with Cane Chairs | 0.05 | 240 | 0.07 | 335 | 0.1 | 480 | 0.15 | 720 | 0.2 | 960 | 0.2 | 960 | 0.2 | 960 | |
Side Walls (Front) | 1400 | Cement plaster | 0.03 | 40 | 0.03 | 40 | 0.04 | 55 | 0.04 | 55 | 0.05 | 70 | 0.05 | 70 | 0.05 | 70 | |
Side Walls (rear) | 1200 | Mineral wool behind perforated plyboard on air gap | 0.7 | 840 | 0.8 | 960 | 0.8 | 960 | 0.7 | 840 | 0.5 | 600 | 0.4 | 480 | 0.3 | 360 | |
Side Partition | 1000 | Plyboard on air gap | 0.6 | 600 | 0.4 | 400 | 0.3 | 300 | 0.2 | 200 | 0.15 | 150 | 0.1 | 100 | 0.05 | 50 | |
Rear Partition | 380 | Resonators | - | 250 | - | 200 | - | 150 | - | 100 | - | 75 | - | 50 | - | 30 | |
Doors | 300 | Wood frame | 0.2 | 60 | 0.15 | 45 | 0.1 | 30 | 0.07 | 20 | 0.05 | 15 | 0.03 | 10 | 0.02 | 5 | |
Stage Furnishing Curtain etc | - | - | - | 250 | - | 300 | - | 400 | - | 500 | - | 550 | - | 600 | - | 600 | |
Air content | 125000 ft2 | - | 0 | 0 | 0 | 0 | 0 | 0 | 0.001 | 125 | 0.002 | 250 | 0.006 | 750 | 0.01 | 1250 | |
Total | 2375 | 2375 | 2520 | 2705 | 2860 | 3210 | 3515 | ||||||||||
Additional absorption due to full audience | 0.35 | 1680 | 0.43 | 2065 | 0.4 | 1920 | 0.35 | 1680 | 0.4 | 1920 | 0.4 | 1920 | 0.4 | 1920 | |||
two-thirds full | 1120 | 1380 | 1280 | 1120 | 1280 | 1280 | 1280 | ||||||||||
one-third full | 560 | 690 | 640 | 560 | 640 | 640 | 640 | ||||||||||
Expected reverberation time full audience | 1.3 | 1.2 | 1.2 | 1.2 | 1.1 | 1 | 0.9 | ||||||||||
two-thirds full | 1.5 | 1.4 | 1.4 | 1.4 | 1.3 | 1.2 | 1.1 | ||||||||||
one-third full | 1.9 | 1.9 | 1.7 | 1.6 | 1.5 | 1.4 | 1.3 | ||||||||||
no audience | 2.4 | 2.4 | 2.1 | 2 | 1.9 | 1.7 | 1.5 | ||||||||||
Measured reverberation time no audience | 2.3 | 2.3 | 1.9 | 2 | 1.9 | 1.6 | 1.2 |
This image is embedded in ...
- Acoustics of the Tagore Theatre, Chandigarh." The Indian Concrete Journal 39, no. 12 (1965). "