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Playing in time: the clock, the tempo, the grid

The problem

The DJ is playing 128 BPM. Your colour chase runs at 120, so it drifts against the kick: for a few bars it looks right, then it's visibly off, then right again. Your movement effect runs at yet another speed because you started it from a different preset. You tap a new tempo, but after the breakdown the next track is at 132 and everything is off again. You switch to BPM detection, and in the breakdown, with no kick, the counter wanders from 128 to 97 to 140 exactly when every change in the light is noticed. And the build-up you planned so carefully ends with the big hit landing half a bar after the drop (what the drop itself should look like is on Busking a rave).

Each chase and effect has its own clock, and none of them knows where the music is.

Practice

This page is working practice for electronic music, built on the speed, rate and trigger tools the manual documents. The manual describes the tools, not how to use them musically.

The musical grid

Electronic music is built on a strict grid, and light that follows the grid feels "locked in":

Unit Length What light usually does on it
Beat one kick (at 128 BPM about 0.47 s) chase steps, pulses, strobe hits
Bar 4 beats colour changes, movement cycles, alternating sides
Phrase 8, 16 or 32 bars look changes: new colour palette, new layer, new position
Section intro, groove, breakdown, build-up, drop energy level: atmosphere, density, speed

Two habits follow from it:

  • Change on the one. New looks land on the first beat of a phrase, not somewhere in the middle. The audience hears the phrase change, so a change that lands with it looks intended.
  • Speed in musical ratios. If one beat is the base, useful speeds are ×2, ×4 (faster) and ÷2, ÷4 (slower; ÷4 is one cycle per bar). Speeds like ×1.5 or "a bit faster" drift against the music.
Section Build-up · 8 bars Drop Bar 1 2 3 4 5 6 7 8 1 2 Beat ×1 pulse on every beat ÷4 one cycle per bar ÷16 one cycle per 4 bars Look what you change build look: add a layer every 2–4 bars cut drop look on the one take something away in the last bar All three layers follow one speed master; the factors keep them in proportion when the tempo changes.
An eight-bar build-up into a drop. Layers at ×1, ÷4 and ÷16 of one tempo; the look changes land on bar boundaries, the drop look on the one.

The idea: one clock, everything follows

grandMA2 has 15 speed masters plus a BPM master that follows the sound input. Chasers, sequence executors and effects can all be linked to one of them. Then the speed master is the tempo of the show: change it once, and every chase and effect follows.

  • Chasers pick their speed source in the chaser settings: Individual (their own speed encoder), Speed 1–15, or BPM from the audio input. A chaser at 60 BPM changes steps once per second, so a chaser on a speed master at 128 BPM steps once per beat.
  • Executors have a Speed Master option (Individual or one of the global masters) and a Speed Factor that multiplies or divides it.
  • Effects follow the speed of the executor they are assigned to. The mini executor shows this as a factor: "60 BPM correspond 1:1". The effect's speed group links it to a speed or rate master.

Put a speed master on a fader with its buttons as Learn, DoubleSpeed and HalfSpeed, and keep it in the same place on every page (see What goes on an executor). Set the speed readout to BPM (Setup → User → Settings → Speed Mode), so the numbers match what the DJ software shows.

To verify in onPC: check 12

Getting the tempo: tap, listen, type

Whatever source you use, it ends up in the speed master the chasers and effects follow. You choose how the number gets there:

Tap it (Learn)
Hold Learn and tap the executor button of a chaser, an effect or a speed master in time; at least two taps set the speed. On a speed master fader, the Learn button does the same. Tap on the kick for a full bar or two, not just twice: a few taps give a rough tempo, more taps a better average.
Let the console listen (BPM master)
Connect audio to Audio In on the back of the console (balanced XLR, at least 20 mV). The Sound Input window shows the frequency bands, the waveform and a BPM counter; its BPM fader follows the detected tempo, with DS, HS and Learn buttons to correct it. Chasers can use BPM as their speed source directly.
Type it
If the DJ software shows the BPM, type it: Speed 128 Executor 3 sets that executor's speed exactly. For a club with one known tempo this is the most accurate way.

Practice

  • Tap drifts. Even a good tap is a little off, and the error adds up over a long track. Re-tap at the start of every phrase where it looks off, or type the DJ's BPM.
  • BPM detection fails in breakdowns. No kick, no beat to detect: the counter wanders exactly when the music is quiet and every light change is noticed. Watch the counter during the first breakdown, and be ready to take over by tapping, or work from a tapped speed master and use the BPM master only to check it.
  • Half or double detection. A detected 64 or 256 instead of 128 is the classic error; that's what the DS and HS buttons in the Sound Input window are for.

To verify in onPC: check 13

None of the three sources knows where the one is: they set how fast, not when a bar starts (see phase below).

Faster, slower, and in proportion

Inside the same tempo you want different layers to move at different musical speeds: pulses on the beat, a colour change per bar, a slow pan over a phrase. Do that with factors, not with separate speed masters:

  • Speed factor per executor (×2, ×4 … ÷2, ÷4 …, up to 32) when it follows a global speed master; chasers have the same in their settings.
  • DoubleSpeed / HalfSpeed as button functions or keywords, per executor or on the speed master. The Masters window has All Double Speed, All Half Speed and All Learn for every speed master at once.
  • Speed 1:1 (chaser) and Rate1 reset to the base tempo.

Because every layer still follows the same master, one tap moves all of them and they stay in proportion. A build-up then becomes: double the speed master every 8 bars (÷2 → 1 → ×2 → ×4), and reset to 1:1 on the drop.

In time, but not together: phase

Two effects at exactly the same speed can still be out of step: one is at the top of its cycle while the other is at the bottom, because they were started at different moments. Same tempo is not the same phase.

  • SyncEffects (hold MA + Effects, or the Sync Effects button in the effect special dialog) restarts all running effects together. Press it on the one.
  • Chasers start from their first step when you start them; start them on the one.

Interpretation

The speed master gives the console the tempo, but nothing in the manual says it knows where the one is. Tap and BPM detection set how fast, not when a bar starts. That's your job: start, sync and change on the downbeat.

To verify in onPC: check 14

Rate, speed and Exec Time are different things

Three faders change time during playback, and they're easy to mix up (see also Timing):

Tool Changes Typical use in a set
Speed (speed master, executor speed) tempo of chasers and effects follow the BPM
Rate (rate master, executor rate) divides cue fade and delay times; effect speed too only with Link Effect To Rate make a look's fades snappier or slower without reprogramming
Exec Time replaces all cue times with one time rough busking, rehearsals

So turning a rate fader up won't speed up your chaser, and turning the speed master up won't make cue fades faster. If a sequence of looks should fade in musical lengths, Stepped Rate (executor option) binds the rate to fixed steps instead of a free value. Executors that must keep their stored times can be set to Ignore Exec Time.

Let the music fire cues

The same sound input can skip the tempo altogether. Every cue has a trigger (the Trig column in the sequence sheet). Besides Go, Time, Follow and Timecode there are two musical ones:

Sound
The cue fires on a sound peak in one of 11 frequency bands, chosen in the Trig Time column. On the bass band this is "the kick fires the cue".
BPM
The cue fires on the beats detected in the sound input. A sequence of looks with BPM triggers steps through them on the beat.

Sound can also drive an effect form: the sound forms follow the frequency bands, with the Snd Fade fader setting how hard (0) or soft (100) the effect follows. That's audio-reactive intensity without any tempo at all.

Practice

Sound and BPM triggers work in the groove and fail in the quiet parts: in a breakdown they either stop or fire on the wrong sounds. Use them on a layer you can switch off (its own executor), not for the main look. For a short programmed moment, a timecode show or a chaser with commands is the precise alternative (see Timecode in a DJ set).

When you need it, and when not

  • Every busked set to electronic music: one speed master for everything rhythmic, with Learn and half/double on buttons. This alone fixes most "the light doesn't fit the music" moments.
  • Long sets with changing tempos: add the BPM master as a reference, and decide whether you trust it or your tap.
  • No audio feed at the desk: tap and type are all you have; tap on a speed master, correct with half/double, re-tap per phrase.
  • One known tempo all night (a resident DJ, a fixed set): type it.
  • onPC without a console: the manual only describes the console's Audio In connector, so don't plan around the sound input on onPC until it's checked (check 13 above).
  • Sound/BPM triggers and sound forms: an extra layer for the groove, not the base of the show.
  • Pre-produced shows to a fixed track: timecode instead of tempo tools.

Sources