Sheet Metal 2.38 mm Round, Glass Wool 90 mm R2.5
Same build with and without the mass-loaded vinyl layer.
Tests
2
Effect of MLV
Rw range
12–29dB
spread 17 dB
Highest Rw
29dB
MLV
Largest ΔRw vs first
+19dB
MLV
Sound reduction index
R′ from the 2270, re-referenced to the 0.9216 m² specimen area (−0.35 dB). Grey lines: reference bounds.
Single-number ratings
Open in explorer| Varies | Test | Rw | C | Ctr | ΔRw vs first | ΔRw vs open | Mean R | |
|---|---|---|---|---|---|---|---|---|
| No MLV | Project045 | 12 | −1 | −2 | ref. | +12 | 10.4 | |
| MLV | Project061 | 29 | −2 | −5 | +19 | +28 | 25.6 |
Rw, C and Ctr per ISO 717-1 over 100–3150 Hz. ΔRw fits the reference curve to the band-by-band difference curve, which is not the same number as subtracting two separately rounded Rw values. Mean R is the arithmetic mean over the 16 rating bands.