BPM and Tempo

Experience BPM, which expresses a track's speed, and the tempo that moves it.

In the previous pages, we looked at beats, bars, phrases, and the structure of tracks.

Next is the speed of a track.

To play two tracks overlapped, a DJ needs to know how fast each track is.

The number that expresses that speed is BPM.

What is BPM?

BPM stands for Beats Per Minute, and it is

the number of beats in one minute.

It is a number that shows this.

For example,

120 BPM = 120 beats in one minute

At 128 BPM, there are 128 beats in one minute.

The larger the number, the shorter the gap between beats, and the faster the track.

Conversely, the smaller the number, the slower the track.

Listen to the difference in speed

Even with the same rhythm, the speed changes when the BPM changes.

For example, compare

120 BPM
128 BPM
136 BPM

by ear, and you can hear that the larger the number, the shorter the gaps in "1, 2, 3, 4."

Pick a speed and listen for the difference in the spacing of the beats

2 barsStopped

Red lines mark the start of a barWhite lines are beats 2, 3, and 4. Count out loud: "1 2 3 4 / 2 2 3 4 / 3 2 3 4 / 4 2 3 4".

In DJ software and on CDJs, the BPM is displayed when you load a track.

By looking at that number, you can check how different the speeds of two tracks are.

Why DJs match BPM

Suppose track A is 128 BPM and track B is 130 BPM.

If you play these two tracks at the same time as they are, the beats may sound matched at first, but they will gradually drift apart.

Track A has 128 beats per minute.
Track B has 130 beats per minute.

That's because track B is slightly faster.

Even if the "thump" of the two tracks sounds at the same timing at first, the positions drift further apart as time passes.

To play two tracks overlapped, you first need to match the speed of the tracks.

Change the speed of a track with TEMPO

DJ equipment has a TEMPO control for changing a track's playback speed.

If track A is 128 BPM and track B is 130 BPM,

you slow down the TEMPO of track B a little,

130 BPM → 128 BPM

to bring it in line.

Now the two tracks' beats move forward at the same speed.

Conversely, if the next track is slower, you raise the TEMPO to bring it closer to the current track.

Changing the tempo also changes the pitch

If you simply change a track's playback speed, not only the speed but also the pitch changes.

Speeding it up raises the pitch, and slowing it down lowers the pitch.

It's the same as how a record's voice gets higher when you spin it faster and lower when you spin it slower.

DJ equipment and DJ software have a function that keeps the pitch as unchanged as possible even when you change the tempo.

Depending on the equipment or software, it is called MASTER TEMPO, KEY LOCK, and so on.

With this, you can do an operation where

the speed changes.
The pitch changes as little as possible.

That is what you can do.

However, the more you change the tempo, the more the texture of the sound may change or sound unnatural.

For now,

changing TEMPO normally changes both speed and pitch.
There is also a function for keeping the pitch.

It's enough to remember this.

* Sound will play. Please mind your volume.

The same spot plays at three speeds. Listen for the difference in the pitch of the voice and the sound.

Try matching to 128 BPM for real

Here, we start with

Track A: 128 BPM
Track B: 130 BPM

Move the TEMPO of track B and lower it to 128 BPM.

* Sound will play. Please mind your volume.

128.0 BPM

Tempo

90%

130.0 BPM

Tempo

Play button (the purple round triangle): the track you press starts playing. While it plays, the button turns into a pause shape, and pressing it again stops the track on the spot.
CUE: press it while stopped and it remembers the current position. The remembered spot appears as a purple flag above the waveform. Press it while playing and it returns to the remembered spot and stops. This is the same idea as real DJ software (rekordbox).
Waveform: the center line is the current playback position, and the track flows from right to left. Press a spot to jump there, and drag sideways to move in small steps. It does not snap to the beat, so you can close a gap by hand. Jumping alone does not change the CUE.
Where you are now: the orange line in the center is the current position. The bar numbers flow below the waveform, so the number under the line is the current bar. There is no separate box for the number.
Beat offset: check whether the red lines of the two tracks line up. When the red lines are half a beat or more apart, "The beats are off!" appears below the waveform. It shows only while they are off. It does not show how many beats off they are, because you can tell from the red lines.
Line colors: red is the start of a bar, white is the beats in between, orange is the current playback position, and lime is the saved CUE. When the red lines of the two tracks line up one above the other, the starts of the bars are matched.
CUE: a lime vertical line and "CUE" appear where you set it. It stays attached to its place in the audio and flows with it, so it disappears when it leaves the 8-bar view. It is not pushed to the edge, because that would make it look as if it were there.
View range: fixed at 8 bars. A and B are drawn at the same width of time, so when the tempos differ, the spacing of the beat lines looks different. Any offset shows up on the screen as it is.
Tempo: the speed of the track changes in steps of 0.5 BPM. Pull down to go faster, push up to go slower, the same direction as the tempo slider on a CDJ. The center is the track's own speed (128 BPM). Because it changes the playback speed itself, going faster also raises the pitch. This is the same behavior as a CDJ without key lock, or a record. Matching the BPM alone does not line up the timing of the beats automatically.
Previewing in headphones: on real gear, you can check a track in your headphones first without sending it to the dance floor. This screen does not have that. Match by listening to the sound that is playing.
EQ (HIGH / MID / LOW): this changes the amount of that band. Turned all the way down to 0, that band cannot be heard, just like the EQ on real gear: when you say "cut", it disappears. When the bass of two tracks overlaps it turns muddy, so try lowering the LOW on one of them and compare.
Fader: this is the volume of that track. At 0 it cannot be heard.
What you can practice with these two tracks: bring in B from bar 9 of A, at the point marked "Play B" in the waveform strip, and overlap them for 8 bars. During that time A is in Drop (chorus) and B is in Intro. At bar 17 of A, where the overlap ends, Vocal begins at bar 9 of B. That is where A should be fully lowered, not where A ends: if you do not lower it, A keeps playing for its remaining 16 bars and stays layered with the Vocal of B. The mark "Cut A" that appears at bar 9 of B is that cutting point. It is 32 beats, or 8 bars, from the start of B. This is one easy way to practice, not the only right answer. You can overlap anywhere you like, and nothing stops you if you do not follow the marks.
Track length: what plays here are edited versions cut out for practice. A is 32 bars and B is 16 bars. Not every real track is built like this. Playback stops when it reaches the end.

Audio credits

AKulakovka, "Pop House"Pixabay Pixabay Content LicenseA 32-bar cut arrived that keeps going for 45 seconds after the 8-bar changeover. According to the accompanying notes, the original was 118 BPM and it was converted to 128 BPM.
BAlex_Morgan, "House Music Classic"Pixabay Pixabay Content LicenseA 16-bar cut arrived: an 8-bar kick intro, then the vocals come in from bar 9. The tempo has not been changed.

Listen to the two tracks at the same time, not just the numbers.

If track B stays at 130 BPM, the beats of the two tracks drift apart over time.

Once you match it to 128 BPM, the drift stops growing.

This is what matching BPM means.

Even with the same BPM, they aren't necessarily in sync yet

This is important.

If track A and track B are both 128 BPM, the speed at which they move forward is the same.

But

A: 1, 2, 3, 4
B: (offset) 1, 2, 3, 4

if the starting positions are offset like this, the "thumps" of the two tracks won't line up.

In other words,

matching BPM = matching speed

is what it does, and

it does not automatically line up the position of the beats themselves.

To overlap two tracks cleanly, you need both

matching the speed
matching the position of the beats

How to match the position of the beats by ear is covered in detail later, in "Manual Beatmatching."

BPM is one of the conditions for mixing

Just because the BPM is the same doesn't mean any two tracks will connect naturally.

As we saw earlier,

beats
phrases
track structure
the sounds actually playing

and more are also involved.

BPM is one of the things you check in order to mix two tracks.