Subject: Re: Melodic consonance From: Alexandra Hettergott <a.hettergott(at)WANADOO.FR> Date: Wed, 12 Jul 2000 02:31:10 +0200Thank 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 >http://neuro.bio.tu-darmstadt/de/langner/forschung.html, >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 only >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 the >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 hearing. >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...). ..... Sincerely, Alexandra Hettergott. _______________________ Alexandra Hettergott 1, avenue des Gobelins /bo=EEte 23 F-75005 Paris/France T=E9l/fax: +33-(0)1-43 31 41 27 M=E9l: a.hettergott(at)wanadoo.fr http://perso.wanadoo.fr/a.hettergott/ ... la noche, peque=F1os ruidos ... sombra y espacio, tierra y tiempo, algo que corre y cae y pasa ... (Pablo Neruda)