Historical
ANSI S1.16-2000 (R2005)
American National Standard Method for Measuring the Performance of Noise Discriminating and Noise Canceling Microphones
This American National Standard describes procedures for measuring the performance of noise discriminating and noise canceling microphones. The signal-to-noise ratio is measured at 1/3 octave band intervals with the desired test source in a diffuse noise field. The noise canceling performance of the microphone is defined as the noise canceling index (NCI), a weighted summation of the signal-to-noise ratios. The NCI of the microphone under test can be compared to the required baseline NCI of a laboratory standard pressure microphone.
Acoustical Society of America [asa]