Heavily upholstered chair, occupied, front side of seat back 7.5 cm, average (series 6)

PTB reference data

Original description

Material properties

Thickness: Seat back front 3 in, seat back rear sometimes, seat top 3.9 in, armrests 0.8 in

Application: seating

Mounting: occupied

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

α_p nach ISO 11654

f (Hz)	125	250	500	1k	2k	4k
α_p	0.70	0.80	0.85	0.90	0.90	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)

Heavily upholstered chair, occupied, front side of seat back 7.5 cm, average (series 6): 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	0.72	0.79	0.87	0.88	0.90	0.89

Measured values as a table (1 measurement)

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Last updated: 09/04/2026