Glass & transparentHighly absorbent

Physikalisch-Technische Bundesanstalt

Source: Manufacturer's product sheet

Value from the PTB table, not verified

Kaefer Microsorber surface absorber, micro-perforated polyester film

Microsorber

PTB reference data

Original description

Material properties

Manufacturer: Kaefer Isoliertechnik

Thickness: 0.105 mm

Wall distance: 100 mm

Perforation: micro-perforation

Hole size: 0.21 mm

ISO 354 – reverberation chamber

α_w

0.60

α_p nach ISO 11654

f (Hz)	125	250	500	1k	2k	4k
α_p	0.10	0.30	0.75	0.70	0.70	0.55

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Value from the PTB table, not verified

Measured values as a table (1 measurement)

Kaefer Microsorber surface absorber, micro-perforated polyester film: sound absorption coefficient αs per ISO 354 by frequency and test build-up
Build-up	α_w	100 Hz	125 Hz	160 Hz	200 Hz	250 Hz	315 Hz	400 Hz	500 Hz	630 Hz	800 Hz	1000 Hz	1250 Hz	1600 Hz	2000 Hz	2500 Hz	3150 Hz	4000 Hz	5000 Hz
0,105 mm · 0,14 kg / m" · 100 mm · zweilagig / 30 mm Abstand zwischen den Folien	0.60	0.06	0.07	0.10	0.21	0.29	0.45	0.65	0.78	0.77	0.75	0.67	0.62	0.68	0.70	0.69	0.64	0.59	0.47

Measured values as a table (1 measurement)

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Last updated: 04/09/2026