When jazz and swing music first hit the radio, people could tell it was different than other music genres. It had a feel to it that hadn’t been expressed in modern music, and it was the music that sparked a whole new generation of music lovers and music clubs. A new study attempts to identify what makes that swing swing.
A research team from the Max Planck Institute for Dynamics and Self-Organization paired up with the University of Göttingen to investigate the rhythmic phenomenon of swing and how the human brain interprets the beat fluctuations. Many musicians feel a discernable difference when they play jazz or swing music, but they can’t explain what they are feeling. Previous understandings of swing music have suggested that there a ratio between the notes that gives swing music its characteristic sound and feel due to microtiming deviations.
In the case of eighth notes that are played one after the other, swing notes are born when the second eighth note is not held for the same amount of time as the first. This is called a swing ratio and can often be at a 2:1 ratio. The swing ratio decreases when the tempo picks up, but it is elongated when the tempo slows down.
The researchers came up with a different theory about the swing feel—that the swing feel had nothing to do with these microtiming deviations. To test their theory, they created an experiment to change these deviations and see if jazz musicians could identify the differences between them.
In the experiment, they changed the timing between notes in 12 pieces of jazz piano music played over drum and bass jazz rhythms in 3 different ways. In one of these changes, they took all the microtiming deviations out completely; in the second way, the doubled the deviations; and lastly, the deviations were inverted.
The recordings were shared with 160 musicians (either amateur or professional) who completed online surveys about if the pieces sounded natural or flawed. They were also asked about the extent of swing evoked from the music.
Surprisingly, the pieces with no microtiming deviations were rated by the musicians as being more typically swing, while the music with doubled deviations were interpreted as the least amount of swing. The pieces which were inverted had very little effect on the swing ratings with the exception of two of the twelve music samples. However, professional jazz musicians that took part in the experiment rated all the pieces of manipulated music as having lower degrees of swing.
It seems that jazz musicians really can tell what makes swing swing, but we still can’t fully explain it!
References
George Datseris, Annika Ziereis, Thorsten Albrecht, York Hagmayer, Viola Priesemann, Theo Geisel. Microtiming Deviations and Swing Feel in Jazz. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-55981-3
