Stone & concreteHighly absorbent

Physikalisch-Technische Bundesanstalt

Source: Sound System Engineering, Don Davis and Carolyn Davis

Value from the PTB table, not verified

Transite, 3/16 inch perforated, cement-asbestos board, 11% open area, paper backed board, mounted over 4 inch air space

PTB reference data

Original description

Material properties

Thickness: 3/16 inch

Wall distance: 4 inch

Perforation: 11%

Backing: paper backed board

Reverberation chamber (ASTM C423 / ISO 354)

NRC

0.65

derived from ISO 354 lab data

α_p nach ISO 11654

f (Hz)	125	250	500	1k	2k	4k
α_p	0.35	0.55	0.75	0.80	0.45	0.45

Create a permanent free account — Access frequency bands, variants and export.

Free. No password required.

Value from the PTB table, not verified

NRC: 0.65 (derived from ISO 354 lab data)

Measured values as a table (1 measurement)

Transite, 3/16 inch perforated, cement-asbestos board, 11% open area, paper backed board, mounted over 4 inch air space: 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
3/16-in · 4-in	0.65	0.34	0.57	0.77	0.79	0.43	0.45

Measured values as a table (1 measurement)

Access frequency bands, variants and export. Create a permanent free account

Last updated: 09/02/2026