It means nothing if he doesn’t have that swing – all you have to do is stagger your timing.
For decades, jazz fans have debated why certain songs have swing — the signature swaying feel that causes feet to tap and heads to bop. Now scientists may finally have an answer to the classic Louis Armstrong song “What Is This Thing Called Swing?” and the secret lies in the timing of the jazz soloists.
After listening to original and digitally altered piano recordings, jazz musicians were more than seven times more likely to rate the music as “swinging” when the soloist’s timing was partially delayed relative to the rhythm section, researchers report on October 6 at Communication physics.
In jazz, musicians are trained to swing eighth notes or extend the length of their downbeats – every other eighth note – and shorten the in-between beats to create a galloping rhythm. But technique alone doesn’t explain the swing, says physicist Theo Geisel. computer generated jazz songs with swaying eighth notes still don’t have the swaying feel of the style (SN: 02/17/22).
Previous research has suggested that swing may arise from differences in the timing between the musicians in a band (SN: 02/01/18). Geisel and his colleagues therefore only changed the timing of the soloists in the jazz recordings on a computer and asked professional and semi-professional jazz musicians to rate the swing of each recording.
Musicians were nearly 7.5 times more likely to rate the music as swingier when the soloists’ downbeats were minutely delayed relative to the rhythm section, but their offbeats were not.
Most musicians couldn’t put their finger on what was causing the effect, says Geisel, of the Max Planck Institute for Dynamics and Self-Organization in Göttingen, Germany. “Professional jazz musicians who have been playing for many years have apparently learned to do so subconsciously.”
The researchers also analyzed 456 jazz performances by various artists and found that almost all of the soloists used downbeat delays, with an average delay of 30 milliseconds. That average held true across the jazz subgenres of bebop, swing, and hardbop, though there were some variations, Geisel says. “For faster tempos, the delays get smaller.”
Looking ahead, Geisel intends to investigate how “casual playing”—a popular style of delaying upbeats and offbeats in jazz—influences swing.