Acoustic Modelling
Porous Absorber Calculator
Helmholtz Absorber Calculator
Multi-layer Absorber Calculator
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10 20 50 100 200 500 1000 2000 5000 10000 20000 Frequency (Hz) 0 0.2 0.4 0.6 0.8 1 Absorption Coefficient Rockwool Rockwool with 10kg membrane Rockwool with membrane
Absorption
Coefficient
Reflection
Coefficient
Impedance
(real)
Impedance
(imag)
Amend
Parameters
Global Parameters
Air temperature: 20°C
Air pressure: 101325 Pa

X Axis: Frequency
Range: 10Hz - 20000Hz
Scale: logarithmic
Resolution: medium

Angle of incidence: 0°
Porous model: Allard and Champoux (1992)
Helmholtz model: Ingard/Allard
Absorber Parameters
Absorber 1 (Rockwool)
400mm Porous Absorbent, 7500 Pa.s/m2
Rigid backing
Absorber 2 (Rockwool with 10kg membrane)
Limp Membrane, 10 Kg/m2
400mm Porous Absorbent, 7500 Pa.s/m2
Rigid backing
Absorber 3 (Rockwool with membrane)
Limp Membrane, 0.1 Kg/m2
400mm Porous Absorbent, 7500 Pa.s/m2
Rigid backing
Absorber 2: Peak absorption at 26.1Hz. Damping=2.46 (high)

Absorber 3: Peak absorption at 439Hz. Damping=1.31 (medium)