Medium upholstered chair, occupied, front side of seat back 2.5 cm, rear side of seat back 0, top of seat bottom 5 cm, arm rests solid, Liverpool, Philharmonic Hall

PTB reference data

Original description

Material properties

Thickness: 1 in, 2 in

Surface: upholstered

Measurement data

Sound absorption

Reverberation chamber (ASTM C423 / ISO 354)

Values per m² of audience area, not per chair or person.

NRC

0.85

derived from ISO 354 lab data

Frequency values

α_p nach ISO 11654

f (Hz)	125	250	500	1k	2k	4k
α_p	0.75	0.80	0.80	0.85	0.85	0.90

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Value from the PTB table, not verified

NRC: 0.85 (derived from ISO 354 lab data)

Measured values as a table (1 measurement)

Medium upholstered chair, occupied, front side of seat back 2.5 cm, rear side of seat back 0, top of seat bottom 5 cm, arm rests solid, Liverpool, Philharmonic Hall: sound absorption coefficient αs per ISO 354 by frequency and test build-up
Build-up	NRC	125 Hz	250 Hz	500 Hz	1000 Hz	2000 Hz	4000 Hz
Measurement 1	0.85	0.74	0.78	0.82	0.85	0.86	0.90

Measured values as a table (1 measurement)

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Last updated: 09/04/2026