Active noise cancellation-performance in a hearing protector under ideal and degraded conditions.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9506, 1994 Jan; :1-12
The U.S. Bureau of Mines study found that the performance of the active noise cancellation hearing protector in a reverberant field was mixed. The performance varied when the conditions changed from ideal to nonideal. The active noise cancellation (ANC) component provided substantial additional noise reduction from 125 to 500 Hz for all testing conditions (broadband noise or pure tones both with and without safety glasses). While the ANC under ideal conditions provided additional attenuation from 500 Hz and below, under nonideal pink noise conditions the ANC amplified noise below the 125 Hz third octave band. There was a middle band of frequencies at which the ANC amplified noise levels ranging from 630 to 4,000 Hz. The results for pure tones showed that attenuations were higher but that they followed the same general trend.
Auditory-perception; Reverberation; Ear-protectors; Mine-safety; Noise-sound; Mining-industry; Hearing-conservation; Hearing-protection
Report of Investigations
NTIS Accession No.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9506