It’s been nearly 100 years since Duke Ellington recorded ‘It Don’t Mean a Thing if it Ain’t Got that Swing,’ a phrase attributed to trumpeter Bubber Miley.

But it’s taken until now for science to catch up and figure out exactly what ‘swing’ is.

It turns out when a musician delays the first and third beats in a four-beat measure by 30ms, it’s far more likely that other musicians will rate it as having ‘swing’. 

“Swing is a salient feature of jazz music, yet its main psychoacoustical and musical components have remained elusive – save the obvious long-short subdivision of quarter notes,” a new study published Friday in Communications Physics reads

“In particular, the possible role of microtiming deviations for swing has been a subject of long-standing controversy.”

To figure it out once and for all, researchers at the decidedly not hip-sounding Max Planck Institute for Dynamics and Self-Organization in Germany (not a country known for having swing in its music) took solos from a few jazz standards and manipulated the timing.

They found when they delayed the downbeats (one and three) by 30s (or 9% of a quarter-note) but left the upbeats (two and four) in place, jazz musos were 7.48 times more likely to say it had swing. 

“No significant difference was found in music that had delays in both the downbeats and the offbeats compared to the piece without any delays.”

The researchers say the finding could help computer musicians add swing to their digital creations. (Image: Unsplash)

Analysis of more than 450 jazz recordings found downbeat delays were present “in almost all performances”, suggesting musicians “use these subtle timing manipulations in their performances to enhance the swing feel” perhaps without consciously doing so. 

“Some professional jazz musicians reported that they could perceive a pleasant friction between soloist and rhythm section, but were amazed that they could not determine its nature,” the paper said. 

“They apparently could ‘feel it’, but they just couldn’t ‘explain it’,” referencing a famous 1940s quote about swing in jazz. 

The researchers say the finding could help computer musicians add swing to their digital creations. 

“Many modern digital audio workstations offer options for ‘swingifying’ computer-generated music. So far these features are of limited value, as they mainly serve to introduce a suitable swing ratio. 

“Adding downbeat delays according to our findings would help improve these features for digital music production.”

But be careful – the researchers found downbeat delays weren’t present in some other genres of music, such as “Latin music of various origins”.