Acoustic Modelling
Porous Absorber Calculator
Helmholtz Absorber Calculator
Multi-layer Absorber Calculator
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20 50 100 200 500 1000 2000 Frequency (Hz) 0 0.2 0.4 0.6 0.8 1 Absorption Coefficient No gap 1mm gap 2mm gap 10mm gap
Absorption
Coefficient
Reflection
Coefficient
Impedance
(real)
Impedance
(imag)
Amend
Parameters
Global Parameters
Air temperature: 20°C
Air pressure: 101325 Pa

X Axis: Frequency
Range: 20Hz - 2000Hz
Scale: logarithmic
Resolution: medium

Angle of incidence: 0°
Porous model: Allard and Champoux (1992)
Helmholtz model: Transfer matrix
Absorber Parameters
Absorber 1 (No gap)
10mm Perforated Panel, 10mm/150mm (0.35%)
50mm Porous Absorbent, 10000 Pa.s/m2
50mm Air
Rigid backing
Absorber 2 (1mm gap)
10mm Perforated Panel, 10mm/150mm (0.35%)
1mm Air
50mm Porous Absorbent, 10000 Pa.s/m2
49mm Air
Rigid backing
Absorber 3 (2mm gap)
10mm Perforated Panel, 10mm/150mm (0.35%)
2mm Air
50mm Porous Absorbent, 10000 Pa.s/m2
48mm Air
Rigid backing
Absorber 4 (10mm gap)
10mm Perforated Panel, 10mm/150mm (0.35%)
10mm Air
50mm Porous Absorbent, 10000 Pa.s/m2
40mm Air
Rigid backing
Absorber 1: Peak absorption at 70.7Hz. Damping=1.19 (medium)

Absorber 2: Peak absorption at 70.7Hz. Damping=1.17 (medium)

Absorber 3: Peak absorption at 70.7Hz. Damping=1.16 (medium)

Absorber 4: Peak absorption at 70.7Hz. Damping=1.05 (medium)

Dotted lines indicate that the model used to estimate absorber properties has been used outside of its applicable range. Results may therefore be less accurate than where a solid line is displayed.