Experience and meaning in music performance
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Experience and meaning in music performance |
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Andy McGuiness This Max/MSP patch models the variable timing characteristics of groove patterns such as the drum break in James Brown’s The Funky Drummer (Brown 1986; McGuiness 2005), and in Tumba Francesca music in Cuba (Alén 1995). The patch has two integrate-and-fire oscillators with natural frequencies in a 3:4 relationship with each other. The slower oscillator is the ‘main’ oscillator, that is the one which models the actual timing output of the drummer. The slower ‘covert’ oscillator and the main oscillator interact and affect each other’s timing to produce the subtle variations in beat length which are characteristic of groove. In the Funky Drummer break, the duration of the bar over the 8 bars is less variable than the duration of the beats which make up each bar. The first beat of each bar in the Funky Drummer break is longer than the others by an amount ranging from 17msec to 32msec, while the period of the whole bar deviates less than 9msec overall. It is this pattern of variation which the coupled oscillator model captured, with the shorter-period oscillator of the coupled pair representing the “overt” oscillator (the one providing the timing for the sounds actually played by the drummer) while the longer-period oscillator is a “covert” oscillator, which distorts the timing of the overt oscillator but does not directly control the timing of the drummer. (Of course, in musical situations where cross-meters are actually played by different drummers in an ensemble, both oscillators would be “overt”, while still distorting the timing of each other.) In October 2007 I made a presentation at the Entrainment Network meeting in Bowling Green, Ohio which featured a computational model (implemented as a Max/MSP patch) of a pair of pulse-coupled oscillators with natural periods in a 3:4 ratio. I showed that oscillators coupled in this way exhibit the same microtiming characteristics.
A single oscillator. The spike at the bottom of the image represents the input to the oscillator, which causes it to fire early and return to zero. Two pulse-coupled oscillators, with natural periods in a ratio of 3 (the main oscillator) to 4 (the “covert” oscillator). The spikes at the bottom of the graph simply show where the two oscillators fired together, and mark where the barlines would occur in the Funky Drummer break. Input from the covert oscillator shortens the 2nd and 3rd beats of the main oscillator, so producing the characteristic Long-short-short-long pattern of the Funky Drummer. Alén, O. (1995). "Rhythm as Duration of Sounds in Tumba Francesca." Ethnomusicology 39(1): 55-71. In The Jungle Groove, Polydor. Hopfield, J. J. and C. D. Brody (2000). "What is a moment? ‘‘Cortical’’ sensory integration over a brief interval." Proceedings of the National Academy of Sciences of the United States of America 97(25). Hopfield, J. J. and C. D. Brody (2001). "What is a moment? Transient synchrony as a collective mechanism for spatiotemporal integration." Proceedings of the National Academy of Sciences of the United States of America 93(3). Kapchan, D. (2007). Traveling Spirit Masters: Moroccan Gnawa Trance and Music in the Global Marketplace. Wesleyan University Press. McGuiness, A. (2005). Microtiming deviations in groove. Centre for New Media Arts. Canberra. Australian National University. http://dspace.anu.edu.au/bitstream/1885/42999/1/MICROTIMING_DEVIATIONS_IN_GROOVE_April_2005.pdf Migliore, M., L. Messineo, et al. (2001). "Quantitative Modeling of Perception and Production of Time Intervals." Journal of Neurophysiology 86(6): 2754. Will, U. and E. Berg (2007). "Brain wave synchronization and entrainment to periodic acoustic stimuli." Neuroscience Letters. |
