"Groove" and its jazz variant "swing" are perhaps some of the most elusive concepts in music. People might describe it as something like: "a rhythmic structure that makes you instinctively tap your foot or nod your head." Which: yes, but also, not incredibly illuminating.
For nearly a century, jazz musicians have tended to be evasive when the question is asked of them, "What exactly is 'swing'?" Some may vaguely claim it's something you just feel. Others might say it's a matter of personal opinion, while still others will quip, "You'd be better off studying quantum physics than trying to explain what swing is."
Answers like these can't help but frustrate the rational musician who wants to understand the essence of groove and apply it in their creative craft. After all, why couldn't one simply take swing recordings, digitize them, and meticulously analyze the timing of notes and musical phrases played by each instrument? Well, actually, multiple programmers—and even a physicist—have indeed done this. And yet, a crystal-clear definition of "groove" remains elusive.
So it’s hard to capture the true nature of this phenomenon with words. Let’s look in another direction, towards the music theorists who were the first to describe it. These professionals managed to graphically represent the metric characteristics of swing. Take a look at the illustration below. In the top row, regular (straight) eighth notes in 4/4 time are marked with black circles. The same black circles in the rows beneath indicate quarter, half, and whole notes.
The weak beats of the eighth notes are designated by white circles. These (pay attention!) are shifted slightly to the right compared to the normal, evenly spaced weak beats played by those same eighth notes. These are swung notes, lagging behind the 4/4 meter.
This part might get a bit tricky for beginners in music theory, but we'll try to tackle it together. When swinging, the strong beats of the eighth notes usually align with the strong beats of a regular rhythm. The weak beats, however, are displaced in such a way that they resemble the pattern of a "dotted eighth note followed by a sixteenth note." Look closer though: the displaced weak swing beats start earlier than the anticipated sixteenth note in such a pattern.
This is almost kind of magical: if we play any phrase on any instrument using the blues scale or pentatonic, composed of the pattern "dotted eighth note followed by a sixteenth note," we'll end up with boogie-woogie or shuffle, not swing.
In swing, the weak beats sound slightly earlier than the aforementioned sixteenth notes in shuffle. Swung beats tend more towards triplets—"three instead of four"—over the span of two quarter notes (in 4/4 time).
But here's the catch: the swung note isn't actually part of a triplet. If we look back at the diagram, we'll see that the swung weak beat (the conditional eighth note) falls slightly earlier than the second note of the triplet. Additionally, when swinging, the weak beats can sometimes be played softer than the strong ones, or vice versa, which further complicates matters for anyone trying to grasp the phenomenon of swing.
Okay, admittedly, this is a lot. To avoid going too crazy, just focus on the diagram. Imagine how it might sound, then give it a try. Better yet, listen to some swing recordings from the 1930s and 1940s while looking at the diagram.
In 2023, physicist Theo Geisel, who had previously worked at the Max Planck Institute for Dynamics and Self-Organization and the University of Göttingen (Germany), decided to determine the exact extent to which beats are delayed in traditional swing. It's worth noting that Theo is also an avid amateur saxophonist, and this topic was of great interest to him.
He chose a recording of the track "Jordu" (a jazz standard written in 1953 by Irving "Duke" Jordan). Specifically, he selected a version that most surveyed musicians unanimously identified as having a swing feel. He discovered that the swinging pianist, in addition to playing with delays before the onset of weak beats, also lags behind the rhythm section by about 30 milliseconds when hitting the strong beats!
As we know, this delay is incredibly brief—it’s shorter than the blink of an eye. And apparently, it’s precisely this delay, in a specific track played at a particular (medium) tempo, that creates the sensation of swing.
Is this getting even more confusing? We’re now faced with another delay, this time at the beginning of the strong beats. And in different tempos, this delay could be longer or shorter. So how do you even measure it?
In practical terms, they don't measure the delay at all. In any way. This is what people refer to as "playing with a laid-back feel," "having a sense of swing," and so forth. It's something that's found through practice.
Nevertheless, the defining aspect of swinging comes from noticeably delayed weak beats, as we discussed above. As for microdelays at the beginning of strong beats, those are more a matter of personal preference with the musician.
As early as the first third of the 20th century, drummers and bass players—who make up the rhythm section itself—began to swing. So, what does that mean? This is where we approach the concept of "groove."
This concept is shrouded in just as much mystery as swing. If we set aside the somewhat vague statements made by musicians, however, we can hone down on groove and say it’s essentially "swing within the rhythm section."
That means in groovy music, it's not just the soloist "floating" with their swing over the rest of the band; rather, the entire rhythm section swings. This is typically audible in drums and bass. Decades ago, swing in the form of "groove" began permeating many genres of pop music. It firmly took root in disco and later dance music.
This is a little exaggerated, but we can kind of divide all of it into two streams. The first stream lacks (or almost lacks) swing. This includes certain subgenres of Eurodisco and, more broadly, Eurodance. Think of the famous duo Modern Talking, whose drum machines and synthetic basses marched along like a regiment of knights.
The second stream is contemporary EDM, which has numerous "groovy" subgenres. For instance, NuDisco can sound straightforward, or it can incorporate swing. House music too. Perhaps the greatest amount of swing ("groove") exists in Afrobeats, although even there you'll also occasionally find tracks as flat as a board.
If we start analyzing examples of dance grooves, both drums and bass can contribute to the groove in a specific track. They can work simultaneously (which tends to be less effective) or separately (which works better). Generally, the groove of either the bass or drums stands out more effectively when one instrument plays a straight rhythm while the other swings over it.
For example, in the famous track "I Like to Move It" by Reel 2 Real and The Mad Stuntman, the synthesized bass mostly sticks to a simple, unswung figure throughout. On the other hand, the drums here are maximally "Afro," and the vocals swing along with them. Our more mature readers probably remember this song. Our younger readers probably just think of it as the lemur song from Madagascar:
Let's also listen to this renowned remix of the SAINt JHN song "Roses" by Kazakh artist Imanbek. Here, the straight kick drum sets the tone, and the style resembles slap house, which often feels like Eurodance on steroids.
Yet, this particular track is quite "groovy." The overall movement is created by a relatively simple bassline, which occasionally emphasizes short syncopated notes on the weak beats and "drops out" on the strong ones.
Listening carefully, we can hear that in "Roses," the bass predominantly appears on the weak beats. What's more, sidechaining from the kick drum is applied to it, and the effect persists even during moments when the kick is silent. This adds an extra "rocking" effect.
EDM producers have long noticed that applying sidechain compression from the kick or an "invisible" kick to the bass and other instruments creates groovy "swings," shifting the emphasis to the second and fourth beats in a 4/4 time signature. This is somewhat opposite from the feeling produced by average European folk dance music, which makes listeners want to nod their heads on the first and third beats.
A similar effect (the desire to physically mark the second and fourth beats) is found in many old-school hip-hop tracks, where the drums are often constructed from samples of funk records.
The issue of creating swing in digital audio workstations (DAWs) using MIDI sequencers and virtual instruments was addressed decades ago by programmers developing these tools. They solved it algorithmically.
Every DAW features quantization effects that snap manually played parts to the project's grid (tempo and rhythm). These effects can mimic swing. The degree of beat displacement is usually set in percentage terms.
Here’s what quantizing a simple dance bass line with swing looks like in Cubase, for example. Note that the quantization is set to 16th notes because, unlike in old-fashioned jazz, modern music often uses swing-like patterns based on 16ths. The “swing” percentage is set to 35 for demonstration purposes:
In the screenshot, we can see that every weak 16th note starts slightly later than it would in a straight rhythm. This is roughly how you can visually "draw" swing (or groove) in the bass.
It's crucial to remember that algorithmic quantization with machine-generated "swing" is a somewhat crude solution. It allows you to create rough drafts, but refining them is going to require manual adjustments.
Since synthetic bass may behave differently depending on pitch and tempo, after quantization, you will likely need to adjust some notes without fully adhering to the rhythmic grid. That's because groove is ultimately determined by ear, not by visual representation.
Sidechain or sidechain-like effects in constructing a swinging dance bass serve as the icing on the cake. They merely emphasize the "bounce" created by the arranger, but cannot generate it on their own if the musical parts aren't inherently "grooving."
Music scholars believe that swing (read "groove") emerges when one part of the rhythm section plays "straight" while another swings. When both drums and bass attempt to swing together, the groove effect is less pronounced, and sometimes it doesn't come across at all, especially in digital music. This is because its creators often draw tracks with a mouse and lack experience in physical music-making.
Ultimately, the best way to develop a successful groove of your own is through extensive listening and the ability to swing live, even moderately well, on any musical instrument. If you learn to feel it with your body, through your motor skills, you'll be able to skillfully imitate swing in digital formats as well.
You can train your body to swing musically by dancing or simply tapping your hands on a table. The key is to feel it in your muscles, connect it with your sense of rhythm, and reinforce it by constantly moving to groovy music as you listen.
Ultimately, those experienced musicians might have had it right all along: it’s something you need to feel.
