noise reduction coefficient
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noise reduction coefficient[′nȯiz ri‚dək·shən ‚kō·i′fish·ənt]
The average over the logarithm of frequency, in the frequency range from 256 to 2048 hertz inclusive, of the sound absorption coefficient of a material.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
noise reduction coefficient, NRC
The average of the sound absorption coefficients of an acoustical material at frequencies of 250, 500, 1,000, and 2,000 Hz, expressed to the nearest integral multiple of 0.05.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.