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Hi All, I am hoping to pick the brains of those more knowledgeable about this than I am. I am reading some classic masking papers with a doctoral student and we have a question about a finding reported by Greenwood (1961).
Greenwood, D. D. (1961). Auditory masking and the critical band. The journal of the acoustical society of America, 33(4), 484-502. In this paper Greenwood examined critical bandwidths using a band widening masking paradigms to measure “masked audiograms” as he systematically widened the bandwidth of a masking noise. In one experiment he looked at growth of masking
for his masked audiograms by systematically increasing the spectrum level (and overall level) of the various noise bands. He did this for noise bands that were narrower and wider than the critical bandwidth. For noise bandwidths that were greater than the critical band he showed a linear growth of masking for tones centered in the noise band (i.e., linear in band masking). However, when the noise bandwidth was
less than the critical bandwidth, growth of masking showed a “jog” in the growth of masking function for tones centered in the narrow noise band. That is masked threshold appeared to decrease (~3 dB) as noise power increased when the level of the noise
reached what he called a “transition level” of around 50 dB sensation level. However, as levels increased above this “transition” level, growth of masking again seemed linear. Figure 6 on p. 493 of the paper shows the finding I am talking about. It would not be the first time I misinterpreted an older (and newer) paper so I am probably just missing something. However, I was not familiar with this finding and wondered if others were aware of it and had thoughts on why it occurred.
Thanks, Ben |