Music Theory 000.1 – Part 6: I’ve Got Rhythm

This is part of my series on Understanding How Music Works. If you haven’t yet, you may wish to start at the beginning.

I think it’s well past time we talked about time, y’know? As I first thought (months ago) about writing this post, I realized that music, of all the arts, has a special relationship with time. I also realized that my goal here was to explain things simply, thereby understanding it well enough myself. And I have not always kept it simple. So I’ll break this post up into the abstract/philosophical part (to get it out of my system) and the simple/practical part.

Music Can Actually Manipulate Time

Depending on how you categorize things (and on how much you pick nits), The Arts can generally be broken down into visual, literary, and performance. Of those, the performance arts are the ones that take place over time (again, unless you get rhetorically fussy with me here). I’ll make the case that of all the performing arts, only Music actually manipulates units of time and our perception of how time moves. It’ll take a couple of logical steps.

In this blog I’ve defined Music as “organized sounds and silences.” I’ve also written about the human propensity to pick up on patterns. One of the very common ways people have organized their musical sounds and silences over time is through the use of beats, or pulses, or… y’know, that part that you tap your foot to. This is true whether the beats are expressly articulated, as in Starship Groove (via the drummers), or not, as in a Mozart minuet.

Let’s consider the latter. The player starts the piece; the listener hears the first sound—a single note—followed a very short time later by another single note. Then, after roughly the same very short amount time, a third sound, two notes together. But then a longer bit of time passes before the next sound—another two-notes-together—happens. About twice as long, as it turns out.

At this point the listener’s brain is scrambling to find a pattern it can use to understand the sounds that it’s hearing. But after a very few seconds, the relative durations, repetitions, and emphases of the notes signal to the listener what the pattern is. “Stuff tends to happen around time units that are about so-and-so long.”

While there are whole other systems (some of which we’ve discussed) that organize pitches in what I guess could be called “pitch-space,” this is a system that organizes musical sounds in time. And I hold that the fundamental unit of musical time is the “beat.” (That could be debated; there’s sufficient reason to consider the “measure” to be this fundamental unit, but I favor the beat. I’ll explain these things, a bit further on.) The beat sets up the expectation in the listener as to when—at what points in time—musical sounds are likely to happen.

So, that was my first logical step: the beat is the fundamental unit of musical time. But how does music manipulate time? By sometimes playing with the listener’s conception of what the beats are, and how they are organized.

Quite by accident, the Mozart piece I picked illustrates this nicely. The performance I linked above is played very crisply and regularly, so you might be able to clearly hear a trick that Mozart plays on the listener, even in such a simple piece as this. Just when we think that the beats are organized in groups of three—one, two, three, one, two, three—Mozart writes a repeating sound that suggests that they might be in groups of two. He quickly resolves the issue (it’s three), but for a while he keeps us guessing, which makes the piece interesting to listen to.

Then there’s what happens when a performer speeds up and slows down the beats, playing this piece.

For an advanced look at what happens when a composer plays with your expectation of the beat, check out He Ran To The Train, between about 3:00 and 5:00. (Listen to the whole thing—it’s a treat!) A drummer friend of mine calls stuff like this “tilting the table,” and has the most fun with it when you can’t tell what’s the table and what’s the tilt. (And I love him for it.)

The Beat and How to Swing It

So, enough for now about music’s magical mystical time-altering superpowers. How does this “beat” thing work, when it’s not getting all clever and slippery?

Let’s consider a piece that does not vary in tempo (by the way, “tempo” = “how fast the beats are going”). “Starship Groove” linked above is a fine example—rock solid unvarying tempo, and the beat is even marked out by some strobing lights on the starship. In such a piece, a “beat” is a unit of time that is typically between about 0.333 and 1.5 seconds long. In “Starship Groove,” each beat is about 0.539 seconds long. You can see that that’s a clunky way to express how long a beat is, so we normally refer to that in terms of how many of those beats would ocurr in one minute. Very slow pieces with 1.5-second-long beats are 40 beats-per-minute (bpm), very fast ones with 0.333-second-long beats are 180bpm, and “Starship Groove” clocks in at about 111bpm.

Musical time is organized around divisions and groupings of this fundamental unit. The divisions—smaller bits of time that a beat is segmented up into—generally contribute to the “feel” of the beat. (This is best heard, not described.) The groupings—measures, phrases, and sections—can also contribute something to the “feel,” but the larger groupings (phrases, sections) generally have more to do with the “form” of the piece.

Subdivisions

Just as a piece of music generally (at least 55% of the time) picks a particular tempo and more-or-less sticks with it for the duration of a piece, so it picks a particular way of slicing each beat into mini-bits, and (maybe 67% of the time or more) uses that way consistently on every beat of the piece. And there aren’t a whole lot of options; we see certain beat-subdivisions so commonly that it’s a reasonable theory that there’s something natural-to-the-human-animal about them. And those subdivisions are:

  • Two. You can count “one-and-‌two-and-‌three-and-‌four-and-‌one-and-‌two-and-‌three-and-‌four-and…” while the music is playing. Like If You’re Gone.
  • Three. You can count “one-two-three-‌two-two-three-‌three-two-three-‌four-two-three-‌one-two-three-‌two-two-three-‌three-two-three-‌four-two-three…” while the music is playing. Like Love Song.
  • Four. You can count “one-two-three-four-‌two-two-three-four-‌three-two-three-four-‌four-two-three-four-‌one-two-three-four-‌two-two-three-four-‌three-two-three-four-‌four-two-three-four…” while the music is playing. Like Radioactive.
  • Six. If you’re really fast, you can count “one-two-three-four-five-six-two…” but that will get tedious fast. As we get used to these things, we dispense with the numbers and either use nonsense syllables or just feel the “feel.” I just came up with this, though, and it’s too good not to share: “one-un-be-liev-a-ble-‌two-e-lec-tri-ci-ty-‌three-math-e-ma-ti-cal-‌four-cre-a-tiv-i-ty-‌one-un-be-liev-a-ble-‌two-e-lec-tri-ci-ty-‌three-math-e-ma-ti-cal-‌four-cre-a-tiv-i-ty…” Try that whilst listening to Superstition, or just take my word for it and let this music slide your backbone.

Because that’s the point, really. Tempo (speed of the beat), subdivision, and measure (the smallest grouping of beats, which I’ll discuss next) have a lot to do with how the music fits in your body, the “feel” of the music, how it feels. When I coach a singer that their instrument is their whole body, top of head to tips of toes, that’s part of what I mean. If you ignore the rhythm of music and how it feels in your muscles and bones, you’re ignoring part of the birthright of human music-making.

But there I go getting all starry-eyed again. Let’s move on.

Big Time—Groups of Beats

What happens when there’s more than one beat in a song, as is usually the case? I’ll simplify a bit here and just discuss the concepts of “measures,” “phrases,” and “sections.”

Just above, I referred to a “measure” as the smallest grouping of beats. This happens quite often: the fundamental pulses of a piece of music sound like they are in a small group of (most commonly) two, three, four, or six beats per group. There’s usually a subtle emphasis on one of the pulses, marking it as the “beginning” of the group, which is why we tend to say “one” when it drops. And usually (again, maybe 67% of the time or more) once a piece has picked how many beats are in a measure, it tends to stick with it.

You might have noticed that I consistently counted to “four” in each of the examples in the bulleted list above. That was mostly for consistency’s sake, and not to be confusing, but I picked “four” because it’s pretty damn popular. But there are certainly plenty of examples of three (Christmas Waltz, Daughters), and even five (Take Five) and seven (Starship Groove, see above).

When we start to consider stretches of time as longer than this, we’re getting beyond a discussion of “rhythm” and venturing into the realm of “form.” But since both have to do with how music unfolds over time, I think “phrases” and “sections” deserve brief mention here. Brief mention. This post is quite long enough already.

The next biggest time-unit, as I see it, is a musical “phrase.” This concept is a little more fluid; there are few hard-and-fast observed tendencies when it comes to phrases, and multiple interpretations of just what constitutes a phrase in a given piece may be valid. But the analogy to a sentence—implied by the name—holds. This seems to be a little musical idea—sometimes two measures long, sometimes four or three or eight or longer—that may or may not be complete in itself, but seems to hang together. It’s not uncommon for one phrase to set up a musical idea, and for the next phrase to answer it.

How to differentiate between a phrase and a section? The best way to convey it may be to say that when it sounds like “okay, that was a thing, now we’re moving on to another kind of thing,” call that a section. In a pop song, I normally consider a verse a section, then there’s sometimes a bridge section, then a chorus section; back to a verse section, repeat the bridge, repeat the chorus, and so on.

And I think that’s quite enough of that. If I’ve left a rhythmic stone unturned, ask me about it in the comments. Also, leave some examples of rhythmic things that you think are interesting. We haven’t really covered what a rapper’s “flow” or a jazz balladeer’s “phrasing” is in relation to all this, and those are topics very relevant to a discussion of rhythm. So, fire away!

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