Re: Vibrato

[John Neuhoff <neuhoffj@xxxxxxxxxxxxxxxxxxxx>]

At 04:58 PM 4/9/98, Richard M Warren wrote:
>...wonder if anyone knows of an
>experimental verification of the phenomenon as described in the following
>quote:
>
>>... in the normal vibrato which involves pitch, loudness, and timbre,
>>even the best ear can not isolate or identify these elements, to any
>>satisfactory degree, by direct hearing.  We make the situation even more
>>critical and striking when we produce experimental tones in which we
>>present either a pitch or an intensity pulsation alone and ask the
>>musician to say which it is.  Even under these circumstances, a good
>>musician is quite unable to say which is which, even when the extent
>>approaches the normal extent for pitch or intensity.  For example, if we
>>have in one case an intensity wave of 5 decibels and in another a pitch
>>wave of a half-tone, he is almost as likely to call the intensity pitch,
>>or the pitch intensity, as to call them correctly.... Many musicians will
>>immediately take exception to this paragraph and say, "There is no danger
>>in my confusing pitch and intensity in the vibrato."  That is just
>>another proof of the vitality of the illusion, because any one who has
>>such a conviction quickly can be disillusioned by submitting himself to
>>the test described.

Although the experiments did not use vibrato, Mike McBeath and I found that
dynamic intensity change influenced perceived pitch in the direction of the
intensity change.  Thus, when frequency and intensity change dynamically,
the percetion of pitch appears to be a weighted vector sum of the two types
of change.  This is experimental evidence consistent with the above quote. =
=20

See:

Neuhoff, J. G., & McBeath, M. K. (1996). The Doppler Illusion: The influence
of dynamic intensity change on perceived pitch. Journal of Experimental
Psychology: Human Perception and Performance. 22 (4) 970-985.=20

Neuhoff, J. G., & McBeath, M. K. (1997). Overcoming na=EFve mental models in
explaining the Doppler shift: An illusion creates confusion. American
Journal of Physics, 65, 618-621.

-John Neuhoff

   =20
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John Neuhoff                    Phone:  610-250-5287
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