Tempo and BPM

So far, we've talked about pitch: which notes, on which rows of the piano roll. In this part, we move to the other dimension of the grid, the one that runs from left to right: time. And it all starts with a number you see every time you open a project, at the top of the screen, often set to 120 or 130 by default. That number is the tempo.

The beat you already follow

Before we define anything, listen to the next figure. It's just a kick hitting at regular intervals, with a clap on every other hit. Let your foot or your head follow along: you don't need any theory to do that.

What your foot followed is called the pulse: a series of regular beats, like the ticking of a clock. Each of those regular hits is called a beat. The tempo is the speed of that pulse, and we measure it in BPM, which stands for beats per minute. At 120 BPM, there are a hundred and twenty beats in a minute, so exactly two per second. At 60 BPM, there's one beat per second, the speed of a clock's second hand.

Don't confuse the pulse with the rhythm. The pulse is the regular grid, always the same, that you feel underneath the music. The rhythm is the way the sounds are placed on that grid: long or short, on the beats or between them. Two tracks can have exactly the same tempo and completely different rhythms. This whole part of the course is about rhythm; this first lesson is about the grid that carries it.

Feel the tempo before you read it

The best tool for working on tempo is your body. Musicians tap their foot, dancers feel it in their shoulders, producers nod their head in front of the screen. That's not a small thing: if you feel the beat, you'll hear right away when a snare comes in too early or when a loop doesn't land back on its feet.

Try the metronome below. Start at 90 BPM and tap your foot along with it, then go up to 130, then down to 70. Notice the speed at which you start wanting to tap on every other click instead of every click: that's your body looking for a comfortable pulse, and we'll see that this urge plays a big part in some genres.

In your software, the metronome is often called “click” or “metronome”, and you'll recognize it by a small metronome icon near the transport buttons. Keep it on when you record a part on the keyboard: playing without a reference means you'll have to fix everything afterward.

Typical tempos by genre

Each genre has its tempo habits, tied to the way people dance to it, to its history and to the gear it started with. These are guidelines, not laws: you'll find house at 115 and techno at 150. But when someone asks you for a trap beat or a house track, these ranges give you a good starting point.

Look at the row for trap, drill and dubstep. The tempo shown is fast, around 140, and yet this music doesn't feel fast at all. On the contrary, it feels heavy, almost slow. That's not a contradiction, and it's what we're going to listen to now.

Half-time and double-time: one tempo, two feels

First, listen to this beat at 140 BPM. The snare lands on the second and fourth beat of each group of four, as it does in most pop or rock songs. In the next lesson, we'll call this group of four beats a bar. For now, just listen: the beat sounds fast, almost nervous.

Let's keep exactly the same tempo, 140 BPM, and move only the snare: it now hits just once, on the third beat. The kick spreads out a little too. The hi-hats don't change, and yet everything seems to slow down by half.

What you just heard is called half-time. The project tempo doesn't move, but your ear locks its pulse onto the snare, and since the snare comes half as often, the track feels twice as slow. That's what lets trap have very fast hi-hats, which make the most of the 140 BPM, on top of a heavy groove that seems to run at 70.

Double-time is the opposite move: you keep the tempo, but you place the snare twice as often, and the track feels twice as fast. In the next figure, the project is set to 85 BPM, a laid-back hip-hop tempo. Yet with a snare hitting between every beat and tight hi-hats, you'd think you were hearing drum and bass at around 170.

The practical consequence matters: the same track can be listed at 70 or at 140, at 87 or at 174, depending on whether you count the slow pulse or the fast one. Both answers describe the same music. For trap and drill, sample packs and producers usually give the fast tempo, 140 rather than 70. Automatic tempo detectors, on the other hand, are often off by a factor of two, in one direction or the other.

Finding the tempo of a track: tap tempo

To find the tempo of a track you're listening to, the simplest method is called tap tempo: you tap a button or a key on every beat, and the software works out the average speed of your taps. Tap at least eight or ten times, because the first taps are rarely steady, and watch the number settle.

The real question is what to tap along to. The safest choice is to follow the kick in music where it hits every beat, like house or techno. In other genres, tap to whatever your foot naturally follows, then ask yourself whether the result makes sense for the genre. If you get 72 on a trap track, the project is very likely at 144. If you get 60 by tapping only on the snares of a pop song, which land on every other beat, the real tempo is 120.

Now that you can feel the pulse, we're going to organize it: in the next lesson, beats are grouped into bars, and each beat is cut into grid cells.