Plaster & sprayHighly absorbent
Data source
PTB reference data
Physikalisch-Technische Bundesanstalt
Source: Sound System Engineering, Don Davis and Carolyn Davis
Value from the PTB table, not verified
Acoustical plaster (Zonolite)
1/2 inch thick trowel application
PTB reference data
Original description
Acoustical plaster (Zonolite)
Material properties
Thickness: 1/2 inch, 1 inch
Measurement data
Sound absorption
Reverberation chamber (ASTM C423 / ISO 354)· 2 variants
NRC
0.75
Frequency values
αp per octave band
| f (Hz) | 125 | 250 | 500 | 1k | 2k | 4k |
|---|---|---|---|---|---|---|
| αp | 0.25 | 0.45 | 0.80 | 0.90 | 0.90 | 0.85 |
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| Compare | Value | |
|---|---|---|
| 1-in | NRC0.75 | |
| 1/2-in | NRC0.65 |
NRC: 0.75 (derived from ISO 354 lab data)
Measured values as a table (2 measurements)
| Build-up | NRC | 125 Hz | 250 Hz | 500 Hz | 1000 Hz | 2000 Hz | 4000 Hz |
|---|---|---|---|---|---|---|---|
| 1/2-in | 0.65 | 0.31 | 0.32 | 0.52 | 0.81 | 0.88 | 0.84 |
| 1-in | 0.75 | 0.25 | 0.45 | 0.78 | 0.92 | 0.89 | 0.87 |
Measured values as a table (2 measurements)
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