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Re: Melodic consonance

Thank you for your answer :
Eckard Blumschein wrote :
>There are people like
>me who consider virtual pitch a plausible result of neural principles
>rather than a "gestalt" phenomenon.
Here again I do have difficulties with your "rather than", while being
in (general) agreement with considering neural principles.
>The same reasoning provides a
>functional understanding of the neural basis for sensations like
>consonance/dissonance on the most basic level, and for more emotional
>judgements like pleasantness at a higher level.
Just "on the most basic level" I wouldn't agree with this view, but
prefer sticking to the distinction between ("basic") "first" (i.e., due
to (both linear and non-linear) "mechanical" processing) and ("higher
level") "second order" (as resulting from neuronal processing) effects,
as CBW-dependent beatings and roughness (or also non-linearly effected
combination/difference tones) opposite to purely "subjective" beating
effects. As to the term "pleasantness" in general I actually would
prefer to take even three different (processing/coding/connotative)
levels into account, the first one being of purely "mechanical", the
second one of neuronal, and the third one of psychological (even
anthropological) nature.
If Roederer is stating here that the auditory system is able to analyze
both the periodicity (as information on frequency) and the temporal
structure (the oscillation pattern, including (periodical) changes in
shape or amplitude) of a sound stimulus of a given duration (cf. e.g.,
pp.43+57 in the German ed.), this is something we might be a little more
familiar with today, in treating ("editing") sound primarily proceeding
from its being represented in the time domain (almost every audio
software does offer this today). Likewise, I do neither have any
difficulties to imagine the ear practicing something like a Fourier
analysis in deriving the "spectral" (i.e., frequency/amplitude vs. time)
from the temporal signal representation, nor do I see the "spectral
component" being something that apart from the temporal aspect at all as
yet already being implied in the notion "frequency" (i.e., the
repetition frequency of an oscillation period per time unit, yet this is
too why I do like the older expression "cycles per second").
>What about acoustic energy, I am aware of many serious reasons to avoid
>this misleading expression.
Okay, imagining it as "acoustic energy received by haircells"... ; yet I
admit that my notion of "spectral energy distribution over time" might
be due to my (conception's) being influenced by "spectrographic"
representations (yet I would be willing to let it drop for the purpose
of a more general consensus...).

>I recommend Auditory Perception by R. Warren,
>Cambridge Univ. Press (1999) and chapter 4 of
>Encyclopedia of Acoustics by Malcolm J. Crocker, Wiley (1997).
>On the web you might find further food for reflection at
>www.uni-leipzig.de/~psycho/kaernbach/pitch.html, and www.leonhard.dk.
>Neurowissenschaft by Dudel/Menzel/Schmidt, Springer (1996)
Thank you for the references, I will look them up occasionally.

>Perception of pitch and musical intervals is only possible by this
>coding of frequency within time domain.
>You may substitute the term frequency by periodicity. With other
>words, if you agree that tonal perception is dually based on both
>tonotopic and temporal coding at a time and in the same neurons,
>neurons certainly interact within time domain.
>Suggested coincidence detection does not just
>provide a simple elucidation to harmony. Other observations can also
>be understood on temporal basis, e.g. the discrepancy between doubled
>frequency and the perceived, slightly enlarged octave.
>Hopefully, you are not confused by my addition that the tonal
perception is
>not the only one but there is also a so called temporal perception in
>sense of modulation transfer, being diffusely spread across tonotopy.
No, I am not (see above), yet I do see the one not being that apart from
the other (as you are saying coded "in the same neurons").
("Experimenting" with adding/repeating (single) periods (of a given
signal) in the time domain I did also find just this "transient" moments
between the sensation of either a (periodic) pulse or a tonal pattern
(in dependence on oscillation period/pattern) particularly interesting,
and, if you want so, "logical".)
>Furthermore, spectral resolution within
>cochlea cannot account for the astonishing frequency resolution of
>This also indicates that frequency discrimination by ear is based on
>perception of period rather than frequency.
I am willing to generally accept this point of view : the perception of
the oscillation period (pattern) being relevant to pitch (sound)
sensation, and, as you are saying, local resonance performing a coarse
spectral analysis, while, however, keeping to seeing both the "spectral"
and the temporal aspects being not that apart from one another (and as
to frequency as such, as being (reciprocally) related to
time/oscillation period...).
Alexandra Hettergott.

Alexandra Hettergott
1, avenue des Gobelins
   /boîte 23
F-75005 Paris/France
Tél/fax:   +33-(0)1-43 31 41 27
Mél:        a.hettergott@wanadoo.fr

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