Re: Masking release due to the pitch-based grouping?

[Michael Kubovy <kubovy@xxxxxxxxxxxx>]

Dear List,

Please note the following sorely neglected article, which shows that 
when one hears a twelve-component uniform-amplitude harmonic complex in 
cosine phase in which a single component has been shifted out of cosine 
phase, the singular component segregates from the complex. At the same 
time, however, the pitch of the fundamental does not seem to be 
affected. The article also shows that if one passes the waveform of 
such a complex through a square-root or cubic-root
compressive transformation, the spectrum of the resulting waveform has 
a peak at the frequency of the singular component.

@article{KubovyJordan1979,
   author =  {Kubovy, M and Jordan, R},
   title =   {Tone-segregation by phase: On the phase sensitivity of 
the single ear},
   journal = {Journal of the Acoustical Society of America},
   volume =  66,
   number =  1,
   pages =   {100--106},
   year =    1979,
   annote = {"This tone-segregation by phase raises doubts concerning 
several current theories of pitch perception. (…) Insofar as these 
results support temporal fine-structure theories of pitch perception, 
they are incompatible with the theories of pitch perception we cited at 
the beginning of this paper (Goldstein, 1973; Terhardt, 1973; Wightman 
1973b)." See summary in http://www.zainea.com/deutch.htm },
}

Some aspects of this work were followed up in:

@phdthesis{Daniel1986,
   author =  {Jane Elizabeth Daniel},
   title =   {Detecting spectral and temporal differences in the 
harmonic complex},
   school =  {Rutgers University, New Brunswick, NJ},
   year =    1986,
   note =    {available from Rutgers's Library of Science and Medicine, 
BF.D184 1986},
}

I haven't seen Gockel et al.'s paper yet, but from Chen-Gia's 
description, this early work is germane to this issue.

> Date:    Thu, 15 Jan 2004 08:47:02 -0500
> From:    chen-gia tsai <tsai.cc@LYCOS.COM>
> Subject: Masking release due to the pitch-based grouping?
>
> …Recently I read a paper about the correlation between the crest 
> factor and masking.
>
> H. Gockel et al. (2003). Louder sounds can produce less forward 
> masking: effects of component phase in complex tones, JASA 
> 114:978-990.
>
> Gockel and colleagues synthesized complex tones composed of unresolved 
> harmonics, which were added either in cosine phase (CPH), giving a 
> large crest factor, or in random phase (RPH), giving a smaller crest 
> factor. The results indicated that CPH tones are louder and produce 
> less forward masking than RPH tones. Thus, it cannot be the case that 
> loudness and forward masking are determined by the same peripheral 
> processes, such as the level of excitation or neural activity. Gockel 
> and colleagues suggested that the representation of these sounds in 
> the auditory system may be affected by at least two processes: 
> fast-acting cochlear compression and suppression.
>
> I am thinking about an alternative explanation of this effect. I 
> synthesized several complex tones composed of unresolved harmonics. 
> They have the same spectrum but various degrees of the crest factor 
> due to different phase relationships of their harmonics. I find that 
> both loudness and pitch strength decrease with the crest factor.
>
> Assuming that unresolved harmonics at n*F0 are better grouped as the 
> pitch strength of F0 increases, CPH is the least effective forward 
> masker because its components are best grouped.
> In my opinion the interesting effect reported in [Gockel et al. 2003] 
> just highlights the importance of auditory scene analysis.
> ______________________________________
> Chen-Gia Tsai
> Ph.D Musicology, Humboldt University Berlin
> tsai.cc@lycos.com
_____________________________
Professor Michael Kubovy
University of Virginia
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