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Re: Rhythm perception

On 15 Nov 2005, at 15:27, Dan Ellis wrote:

We were discussing rhythm patterns the other day and the question came
up about how one determined the start of a pattern.

I think this is the "downbeat detection" problem, which is distinct from
the problem of deciding the main repetitive period of the rhythm
i.e. the spacing between downbeats.

"beat induction" (footapping, beat tracking, tempo tracking etc) has (at least) two components: phase and period. Longuet-Higgins & Lee (1984) determine both of a given rhythm, Large & Kolen do a similar thing using a couple oscillator model.

Ed with probably join is as well ...:-)


I'm not a musicologist, but I've
tried to build a system to align downbeats in different rhythm patterns,
so I've thought about it a little.

Here's one piece of evidence: Tristan Jehan presented a poster at the
recent Mohonk WASPAA on a machine learning approach for predicting
the downbeats, which he tested on a style of Brazilian music called
maracatu.  He played the maracatu examples to listeners familiar with
northern-hemisphere western music, and they could not identify the
downbeat - but of course maracatu fans have no problem indicating the
appropriate downbeat.


That to me is powerful evidence that downbeat is a cultural norm and not
strongly based on some universal.



Henkjan Honing
E honing@xxxxxx
I http://www.hum.uva.nl/mmm/hh/

Music Cognition Group
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