Toward a theoretically based DRC for impulse noise

Abstract

The presently accepted damage‐risk criterion for impulse noise [CHABA. Rep. WG‐57 (1968)] makes no specific allowance for the spectral tuning of the ear. Data from the cat ear, reported at the 9th ICA (G. R. Price, 1977), indicate that the stapes displacement at the threshold of loss for spectrally simple impulses declines as a function of frequency at about 6 dB/octave. Assuming a similar pattern to hold for the human ear, a curve relating the free‐field peak pressure levels of gunfire impulses to the threshold of loss has been developed. The curve allows progressively less pressure (−3 dB/octave) as the spectral peak of the impulse rises to the midrange and allows increases in pressure if the spectral peak is higher than that. For the low‐frequency impulses (most gunfire) this is the opposite of the CHABA prediction. Validation with experimental ears and weapons impulses remains to be done.