Bare Concrete Acoustic Properties \u2014 Absorption Coefficients (125Hz\u20134kHz)
Untreated cast concrete surface. One of the most reflective architectural surfaces. Exposed concrete soffits in modern buildings create significant reverberation unless treated with suspended absorbers.
Absorption Coefficients by Octave Band
| Frequency (Hz) | 125 | 250 | 500 | 1000 | 2000 | 4000 |
|---|---|---|---|---|---|---|
| α (absorption) | 0.01 | 0.01 | 0.02 | 0.02 | 0.05 | 0.07 |
RT60 Impact
Bare concrete adds reverberation rather than reducing it. Replacing 20m² of concrete with absorptive treatment can reduce RT60 by 0.4-0.6s
Frequently Asked Questions
What is the NRC of Bare Concrete?
Bare Concrete has an NRC (Noise Reduction Coefficient) of 0.05, calculated as the arithmetic mean of absorption coefficients at 250, 500, 1000, and 2000 Hz per ASTM C423.
Where is Bare Concrete typically used?
Bare Concrete is typically used as a floor and ceiling and wall treatment. Untreated cast concrete surface.
How much does Bare Concrete reduce RT60?
Bare concrete adds reverberation rather than reducing it. Replacing 20m² of concrete with absorptive treatment can reduce RT60 by 0.4-0.6s
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