Kostenloser Schall Transmission Loss Rechner
Schätzen Sie wall transmission loss unter Verwendung von the mass law. Kostenloser building acoustics Rechner.
Transmission Loss
32.70 dB
Transmission Loss vs Frequency
Formel
Mass Law for Sound Transmission Loss
The mass law gives the theoretical TL of a single homogeneous panel.
Formula
TL = 20 log10(f m) - 47.3 dB
Doubling the mass or frequency increases TL by about 6 dB. This is the field-incidence mass law, valid below the coincidence frequency.
Lösungsbeispiel
20 kg/m2 concrete panel at 500 Hz.
- 01TL = 20 log10(500 * 20) - 47.3
- 02TL = 20 log10(10000) - 47.3
- 03TL = 20 * 4 - 47.3
- 04TL = 80 - 47.3 = 32.7 dB
Häufig Gestellte Fragen
Why does the mass law fail at certain frequencies?
At the coincidence frequency, bending waves in the panel match the airborne sound wavelength, causing a dip in TL. This frequency depends on panel stiffness and thickness.
How can I exceed the mass law?
Use double-leaf constructions (two panels with an air gap), add damping, or use different-thickness panels to avoid common coincidence frequencies.
Is thicker always better?
Heavier is better within the mass-law regime. Very thick panels of the same material are also stiffer, which can lower the coincidence frequency and reduce TL at mid frequencies.
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