Dear Kevin:
Let me assure you that you CAN stream the multiple octaves in a
Shepard tone; in fact, this is what most musicians do. They are
"analytic listeners", unlike myself for example, who just hears
(mainly) a single pitch. However, even if you stream the octaves,
you should hear any particular stream as continuously descending as
long as you hang on to it. If you switch attention to another stream
because you want to focus on a particular octave, then of course the
descent will be interrupted and reset. The point of Madison's
illusion seems to be that listeners hang on to a chosen beat level
for a long time, even when the beat becomes unreasonably slow (or
fast). However, it is unclear how obligatory this tendency is, and
how aware participants are of the continuous change in beat rate.
The willingness to switch from one beat level to another could
probably be manipulated through instructions.
Best,
Bruno
Kevin Austin wrote:
Hmm .. I do not consider this to be an illusion. In my first theory
class I will have six students in front of the class 'beating time'
to a (simple) Sousa march. http://www.youtube.com/watch?v=xvWLMkxSwIo&feature=related
The demonstration is that the division of time (also called
rhythm) is multi-dimensional. Underlying patterns / structures are
(in western music) found from the levels of pulse, beat-subdivision
(grouped pulses), beat (grouped beat-subdivisions), meter
(patterned beats), phrase sub-division (collections of metric
units), phrase (multiples of phrase sub-divisions), phrase groups ...
In western music, around these frameworks, there are rhythmic
elements (melody, accompaniment, figurations etc).
Continuous acceleration / deceleration can be found in the Carter
String Quartet No 2 (1959), http://www.youtube.com/watch?v=YC6qTmsAnQI&feature=related
and in other pieces after that date. The idea of pulse
acceleration is also explored in Kontakte by Stockhausen.
Drummers (and organists) are well-acquainted with this multi-
dimemsional aspect of the articulation(s) of time (rhythm) as they
will often have to provide two or more levels of the metric
structure. Conductors train to be able to move their arms at
different tempi (up to about 3:4), and also to count different
numbers of beats with each arm (3 beats in the left hand and 4
beats with the right).
Regarding the Risset, and shepard tones, I do not hear continuous
descent as I tend not to integrate the tone but stream the multiple
octaves, something I am told I cannot do. http://www.youtube.com/watch?v=cUNjbNK5Giw&feature=related
For the beat and other 'illusions' : http://www.youtube.com/watch?v=e6JSTkwXg90&feature=related
This site is based upon the belief that an external reality exists.
IMV.
Kevin
Date: Tue, 8 Dec 2009 20:17:38 +0100
From: Leon van Noorden <leonvannoorden@xxxxxxx>
Subject: auditory illusion
Dear list,
For those who are looking for a compelling auditory illusion I can
recommend the article by Guy Madison on seemingly perpetually
slowing down or speeding up rhythmic patterns.
The freely accessible paper is located at: http://dx.plos.org/10.1371/journal.pone.0008151
Leon van Noorden
--
Bruno H. Repp
Haskins Laboratories 300 George Street
New Haven, CT 06511-6624
Tel. (203) 865-6163, ext. 236
Fax (203) 865-8963
http://www.haskins.yale.edu/staff/repp.html