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Advanced Tempo & Beat Control In Digital Performer

Digital Performer Tips & Techniques By Robin Bigwood
Published May 2006

You don't always need Live or Melodyne to make your audio elastic — DP can do it too.You don't always need Live or Melodyne to make your audio elastic — DP can do it too.

When it comes to controlling sequence tempo and imposing a meaningful beat structure on freely-recorded MIDI and audio, DP has plenty of tricks up its sleeve — including Live-like 'liquid audio' powers.

In last month's Performer Notes, I looked at DP 's Conductor Track, and how the Adjust Beats feature can be used to build a flexible tempo map to track the varying tempos of a MIDI or audio performance that was not recorded to a click. Adjust Beats works superbly well when you're aligning DP 's time ruler with rhythmic MIDI data, or soundbites that have clear transient peaks. Without these visual cues, though, dragging and placing beats can be a real headache. There are ways around this, such as the technique I described last month, whereby you record a MIDI note 'beat track' while your sequence plays back and then align time-ruler beats to that. But often you can do just as well by using another feature: Record Beats.

Record Beats can be seen as a quicker, 'automatic' version of Adjust Beats. It allows you to take a sequence featuring MIDI data or audio that does not align with DP 's time ruler and metronome and tap along to it on a MIDI device, creating a Conductor Track tempo map for it. Once this is in place, working with your sequence is much more logical. Record Beats works better than Adjust Beats in situations where an audible pulse in the music is not reflected visually in the sequence's audio or MIDI data, or where your sequence has periods of silence or inactivity where pulse is only implied. Its success does, however, rely on your ability to tap rhythmically — so make sure your timing is nice and tight!

Using Record Beats

To see what Record Beats could do for you, let's consider a couple of different practical scenarios and work through them. In both cases I've mocked up some simple but representative material to work on. You can, of course, try the same or work on a 'real' sequence, if you have something appropriate to hand. You'll need a MIDI input device, set up and working correctly, plugged into your Mac. The first example covers the situation of recording beats for a guide or backing track that was not recorded to DP 's click. I'm going to record beats for a sequence in which I've recorded myself giving a spoken count-in before bashing out eight bars on the piano, in the same tempo. The audio wasn't recorded to a click and doesn't match DP 's time ruler at all. This is typical of the form in which you might receive a backing track, guide track, or working version of a song that you need to develop further (see screen opposite).

Here's the 'count-in' audio. You can clearly see the four-beat spoken count-in, followed by about six bars of chords. Using Record Beats, with its 'Tap is first beat' option, you only have to tap a MIDI controller in time while the audio plays back, to give it an accurate Conductor Track tempo map.Here's the 'count-in' audio. You can clearly see the four-beat spoken count-in, followed by about six bars of chords. Using Record Beats, with its 'Tap is first beat' option, you only have to tap a MIDI controller in time while the audio plays back, to give it an accurate Conductor Track tempo map. 1. Start by placing the playback wiper just before the spoken count-in.

2. Open the Record Beats dialogue box: go Project menu / Modify Conductor Track / Record Beats. You want to be able to listen to the count-in before starting to tap along to the audio, so choose 'Tap is first beat', and make sure the 'Shift data to' option is unchecked. You'll see why in a moment.

3. Click OK (or hit the Return key) to start playback of the sequence. Listen to the spoken count-in and when the first beat of the song is reached, start playing any individual note on your MIDI input device in time with the beat. Duration or exact pitch is not important.

4. Continue to tap until the song is over, and don't be put off if nothing in your sequence, including the Conductor Track, changes while you're tapping, even if you change tempo.

5. When you reach the end of the song, finish tapping and stop DP 's playback. At this point you should see the Record Beats dialogue box disappear, Conductor Track tempo data being entered, and possibly some shuffling of the soundbite's appearance.

6. You're almost there — but one crucial step remains. You need to align the first beat of your backing track with a bar line in your sequence. Hit Apple-A to select your guide track and all the new tempo data, then place your mouse pointer on the part of the soundbite that represents the first beat. Click and drag this left or right to align with a bar line (holding down the Apple key if necessary, to override the edit grid resolution and allow much finer dragging accuracy), then release the mouse button.

In this screen, I've selected all and dragged the first part of the 'chords' waveform into line with a downbeat,  in the Sequence Editor.In this screen, I've selected all and dragged the first part of the 'chords' waveform into line with a downbeat, in the Sequence Editor.To ensure that everything has worked as expected, turn on DP 's metronome, rewind to the start of the sequence and start playback. If all has gone according to plan, DP 's metronome will now synchronise exactly with the beats in your audio.

In this situation, your audio hasn't changed but the Conductor Track has, so you need to be careful about getting the two out of alignment. Similarly, modifying any of the tempo data entered by Record Beats will generally result in chaos! However, you now have a Conductor Track that 'maps' the tempo of your guide audio track. You're free to add MIDI parts, record new tracks in time with the metronome and locate to points in your sequence using logical bar and beat locations.

MIDI Performances

You might be wondering at this point about the 'Shift data to' option that was unchecked in this first example. It's basically a convenience feature that can help in some situations — it tells DP where in the Conductor Track to place the first tempo data entry. However, it doesn't help much with recording beats for audio, because soundbites stay in their original recorded positions and the audio and Conductor Track are instantly misaligned. But with a MIDI performance it can work splendidly — so here's our second example, which demonstrates recording beats for a freely-played MIDI backing track not recorded to a click. The situation is somewhat different from our first example. First, there's unlikely to be any kind of count-in. Second, it's trivially easy to find the location of the first MIDI note. Armed with this information, we can record beats, but we do it with more suitable settings:

With freely-played MIDI as a starting point, the 'OK is first beat' option can work better. Here, the playback wiper has been set to align with the start of the first MIDI event. This will define 'beat one' after 'OK' has been clicked.With freely-played MIDI as a starting point, the 'OK is first beat' option can work better. Here, the playback wiper has been set to align with the start of the first MIDI event. This will define 'beat one' after 'OK' has been clicked. 1. With your click-less, free-time MIDI performance in place, select the first MIDI note in the Sequence Editor or Graphic Editor. The information bar towards the top of the window will tell you the note's location in measures, beats and ticks.

2. Put the playback wiper at this precise point: hit the dot key on your computer's keypad, type the measure number, hit dot again, type the beat number, hit dot again, and finally type the beat sub-division value in ticks. Then hit Return. If you're using a laptop without a separate keypad, start off by hitting Apple-T, then type the measure, beat and tick values, separated by the Tab key. Finally, hit Return.

3. Bring up the Record Beats window, as explained earlier. and select 'OK is first beat'. (See top screen of the pair to the right.) This works perfectly, as we're already precisely aligned on beat one and have no need for a count-in. Clicking OK, and thereby starting playback, will get us going on beat one. However, before doing this, check the 'Shift data to' option and type in a measure and beat value. If your performance starts on a downbeat, measure one/beat one should work. But if it starts with 'pickup beats', set a beat value to match. If your sequence was in a 4/4 meter and started with a single pickup beat before the first complete bar, for example, you'd probably set bar one/beat four. Whatever you do, pick a location before the current first note event, but not so early that you're trying to place data before the start of your sequence!

4. Now, get poised with your MIDI controller, and then click 'OK', or hit the Return key. Sequence playback begins. Start tapping your MIDI device on every beat, from the second beat onwards.

5. Continue until the end of the MIDI track, then stop playback. The tempo data you provided should now have been entered, starting from the point you specified in the 'Shift data to' fields. Your MIDI notes should also have jumped to the same location, so no additional alignment is required (see bottom screen). DP 's metronome, after you've turned it on, should now match your MIDI performance perfectly.

Record Beats 'Gotchas'

The above examples keep things simple, but that's fair enough — you're most likely to use Record Beats at an early stage of sequence development, when you might have only a single audio or MIDI track in your sequence. And if you want my advice, you'll always keep it that simple! That's because Record Beats, with the 'Shift data to' option, is capable of doing some apparently bizarre things to your sequence if you're not careful. This is especially true if you start recording beats some way into a region of pre-existing data, if you don't keep tapping until the end of your sequence, or if you opt to shift data later than its original position. In these situations, data can be duplicated, or overlapped with the existing data — not a pretty sight. The golden rules, then, are:After you've tapped along with the MIDI performance, the data is automatically moved to bar two, beat one, and, as if by magic, everything aligns (give or take the odd sloppy tap!)After you've tapped along with the MIDI performance, the data is automatically moved to bar two, beat one, and, as if by magic, everything aligns (give or take the odd sloppy tap!)

  • Always Record Beats starting with the playback wiper to the left of any data in your sequence.
  • Always Record Beats right to the end of your performance.
  • If you use the 'Shift data to' option, always choose a value before the first data event of your sequence, but not before the sequence start. If this means you first need to shift all your sequence data along a couple of bars, so that you have some room at the beginning of your timeline, then do so.

Record Beats Vs Time Signatures

The other thing the Record Beats window doesn't tell you is that it assumes you're working in a 4/4 time-signature and that your beats are a quarter-note long (crochets). This is understandable, as DP has no means to guess otherwise, but it may not suit your material. If your sequence is in another 'something/4' meter (such as 3/4) with a quarter-note beat, there's no problem — Record Beats doesn't actually enter new meter data in the Conductor Track. But there could be an issue if you're imagining your piece with, say, a compound (shuffle) meter, such as 6/8. DP definitely won't accommodate the dotted-crotchet beats this time signature uses. So how do you get around this?

In some situations, you may decide you don't need to. After Recording Beats, you'd end up with quarter-note beats sub-divided into three — triplets — and this sounds exactly the same as a true compound beat. You'd also have to remember to use triplet edit grids and quantisation settings for subsequent work on your sequence. If you absolutely need compound beats, though — perhaps for scoring purposes or later MIDI file export — use the Change Meter window. This is found in Project menu / Modify Conductor Track. Simply type in your new time signature, set the compound beat duration in the 'metronome click' section, type 'from' and 'to' values to cover your sequence from its first bar to its end, and select the 'Only move barlines' option. Finally, click Change. This leaves all your data intact but re-interprets the barring. Very simple.

'Liquid' Audio

DP can do a lot, but it has never pretended to have the real-time audio-warping capabilities of something like Ableton's Live. If you've tried Live, you'll know what I'm talking about — squeezing and stretching audio clips into entirely new rhythmic patterns, courtesy of Warp Markers — and you'll know how useful and creative it can be for some musical styles.

When you combine Conductor Track tempo information with DP's time-stretching capabilities, soundbites can become quite 'liquid'. The steady rhythm in this soundbite is about to be transformed into something more irregular.When you combine Conductor Track tempo information with DP's time-stretching capabilities, soundbites can become quite 'liquid'. The steady rhythm in this soundbite is about to be transformed into something more irregular.So are we DP users completely denied this sort of audio manipulation? In short, not at all, as long as we accept that it has to take place 'offline' — not in real time. The key to making audio 'liquid' is a soundbite's internal tempo map, or so-called Soundbite Tempo. All audio recorded in DP is automatically given one, while audio imported into DP usually isn't, but can be equipped with one. Often Soundbite Tempo will simply consist of a 'stamp' of DP 's overall sequence tempo that was in place when the soundbite was recorded, but it's equally possible for it to vary over the duration of a soundbite — it's as if each soundbite has its own little Conductor Track.

So how does Soundbite Tempo help us do Live-like warping? Well, once DP knows about a soundbite's internal 'beat structure', it can use that information to synchronise the audio with the prevailing sequence tempo, using its Pure DSP time-stretching algorithm. Given that sequence tempo can vary, courtesy of the Conductor Track and the Adjust Beats feature, interesting opportunities begin to open up.

This sort of audio manipulation in DP has a bit of an experimental feel to it, and is certainly easier to understand when there are fewer variables involved. For that reason I'd always recommend not trying to do it with soundbites nestling in a sequence containing other tracks of audio and/or MIDI. Instead, create a new, blank sequence in your project and drag soundbites you want to work on into that. If you produce something you like, drag it into back into your 'main' sequence.

Alphabet Street

To get a feel for the kind of thing that's possible, here's a practical example to try out. I'm going to walk through the process of radically changing the rhythmic structure of a simple soundbite — a recording of me speaking letters of the alphabet steadily, from 'A' to 'H' — using the Adjust Beats feature. This hasn't been recorded to a click and doesn't match the sequence tempo. For clarity, I've edited the soundbite so that it starts directly when I say 'A' and finishes just after 'H'. My intention is to make it sound as though I counted in a completely different rhythm, as follows:

At last, the Adjust Soundbites to Sequence Tempo command is used to 'warp' the soundbite into its new rhythmic structure. This is a fast process on recent Macs, and can sound very good.At last, the Adjust Soundbites to Sequence Tempo command is used to 'warp' the soundbite into its new rhythmic structure. This is a fast process on recent Macs, and can sound very good. A [rest] B-C D E [rest] F-G H

1. With my soundbite displayed in the Sequence Editor, and precisely aligned with a first beat of a bar, I switch sequence Tempo Control to the Conductor Track. Then I go Project menu / Modify Conductor Track / Adjust Beats (see screen above).

2. My first step is to pull beats around in the time ruler to define the new rhythm I'm after. I need freedom to drag beats forwards or backwards by whatever amount I want, so I set Adjust to 'Beats' and select 'Move all following beats by the same amount'. This ensures that as long as I work from left to right, at least initially, I won't end up trying to drag one beat over the top of another, which could happen if I'd chosen 'Move one beat at a time'. Finally, I check the 'Drag beats in Graphic Editor' box, so that I can start dragging.

3. For this example, I need to place my 'B' on the third beat of the bar. To do this, I point to bar one, beat three in the time ruler and drag this left to align visually with my spoken 'B'. Now I need 'D' to fall on bar one, beat four — I'm going to assume that my 'C' will take care of itself and sit equally spaced between 'B' and 'D'. So I grab bar one, beat four in the timeline and simply drag this to align with 'D'.

4. I carry on, putting beats where I want them — bar two, beat one aligns with 'E', bar two, beat three with 'F', and bar two, beat four with 'H'. Finally, I roughly align bar three, beat one with the end of my alphabet soundbite, to make sure that the last beat is dealt with.

What have I got so far? My audio looks a bit different but sounds the same as ever (see screen below). However, I now have timing information in my conductor track that describes a completely different rhythmic structure for my sequence. And this is where the clever bit starts...

Using Adjust Beats, the time ruler's bar and beat lines can be dragged relative to the soundbite, to define a new rhythmic structure for it. It looks as if the audio has already changed, but it hasn't... yet.Using Adjust Beats, the time ruler's bar and beat lines can be dragged relative to the soundbite, to define a new rhythmic structure for it. It looks as if the audio has already changed, but it hasn't... yet. 5. My soundbite still carries the tempo map it was given when it was recorded. This clearly doesn't match the varying sequence tempo, and I can see this because of the red vertical lines that have appeared within the soundbite, signalling the mismatch. But I can 'tell' it about the new rhythmic structure. So I select it, then choose Copy Sequence Tempo to Soundbite, from the Audio menu. At this point the red lines disappear.

6. This still doesn't change the audio, but I'm about to. With the tempo data that was created in the Conductor Track safely transferred to the soundbite, I select all of it and delete it, so that the Conductor Track is empty once more.

7. Now I need to choose a new tempo for the soundbite, so I enter a single tempo event of 120bpm (just as an example) at bar one, beat one of the Conductor Track. Suddenly the soundbite signals a tempo-map mismatch once more.

8. And now the pièce de résistance. With the altered rhythmic structure 'inside' the soundbite, and a single static tempo in the Conductor Track, it's finally time to liquify the audio. Select the soundbite and choose Adjust Soundbites to Sequence Tempo from the Audio menu.

The soundbite readjusts itself, stretching or compressing where necessary, to resolve its internal rhythmic structure to the Conductor Track, and I'm left with the new rhythm I decided on (see screen below). Wonderful!

Practice Makes Perfect

It's well worth experimenting a little with this technique, to really get under its skin, because when you do the possibilities are endless. You can take regular rhythms and make them irregular, or vice versa, or just go mad and stretch single beats out to ludicrous durations. Some of these experiments yield results that can be edited down and exported to a sampler, for example, for really unusual pads or drum sounds. But you can equally incorporate your liquified loops back into your main sequence, to provide entirely different rhythmic accompaniments.

There's yet another approach too — directly writing tempo data into the Conductor Track, rather than using Adjust Beats. This is harder to control, but the results can be astonishing. For more on this idea, you can read the Performer Notes article I wrote in June 2001

Published May 2006

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