Digital Performer: Looping

How do you create a four-minute masterpiece out of just a few measures? And what's the best reverb to make you sound like that drumming gorilla on the TV ad? These questions, and more, answered in this month's Digital Performer workshop...

Loops in DP don't look all that exciting, but are hugely useful. Here the loop tool has been used to loop a two-measure MIDI drum pattern eight times.From 1960s minimalism to the most cutting-edge dance and electronica, loops are the foundation of a vast range of musical styles. Compared to DAW software specifically set up to work with loops, DP often appears resolutely 'linear', not even offering the object-based editing of Logic. In fact, though, it has some great tools for creating and manipulating loops, and in true DP fashion there are often several different methods you can choose from to achieve the same effect, letting you decide which will suit your working style best.

So in this month's Performer Notes we're going to take in a range of features, namely the Loop tool, the Repeat command, and the Paste Repeat and Merge Repeat commands. All of them are hugely useful, as we'll see.

Constructional Loops

Here's a common occurrence: you've recorded a great two-measure riff or drum pattern in a MIDI or audio track, and you quickly want to extend that out to fill an entire 16-measure section, as a guide for laying down more tracks. One insanely easy way to do this is with the Loop tool. Try this, which is pretty much what I've done in the screenshot above:

1. Switch to the Sequence Editor and make sure you can see your track and the riff or pattern you want to loop.

2. If it's not open already, open the Tools palette by hitting Shift-O. Then select the Loop tool (which looks like an arrow chasing its tail) either by clicking on it or tapping the 'L' key twice in quick succession.

3. Set DP's edit resolution grid to crotchet/quarter-note. This ensures you get a musically useful loop length that's properly aligned with the beats and measures in your sequence.

4. Now move your mouse pointer into your riff's track lane; the pointer should turn into a mini loop-tool symbol. Then just drag from the start of your riff to the end, selecting complete measures.

5. In the event information strip (DP4/5) or palette (DP6) you'll now see information about the loop: its start and end locations and, crucially, the number of repeats. In this example we want our loop to repeat eight times to fill the 16 measures, so click where it currently says '2' and enter '8' instead. Job done.

A loop like this appears in the Sequence Editor as a two-part horizontal bar — a transparent 'source' section and a darker, translucent 'loop' section to the right. You'll see that it has two thin vertical 'handles' too. Drag the one on the left to reposition the whole loop and the one on the right to change its length. But the number of repetitions can only be changed in the event info bar (or palette), after first selecting the loop by clicking on one of those handles. Deleting a loop is easy: click a handle to select it, then hit the backspace key.

One thing you soon notice when using the loop tool is that it can only work on one track at a time. What if you want to loop multitrack material? For that task, there's a menu command called Set Loop. Begin by making a time-range selection of the part of the tracks you want to loop. One good way to do this is to drag in the time ruler, then click (and if necessary shift-click) the names of all the tracks to be included. Then, in the Region menu, choose Set Loop... A dialogue box appears, with loop start and end times that should correspond to your time-range selection. However, be prepared to tweak the end time in DP5, because it's sometimes a bit out. There's also a field for the number of repetitions, so set this as required, and hit OK. Again, job done.

How you use the loop tool varies a bit between different editing windows. To start with, you can't use it in the Tracks Overview (although 'Set Loop' still works fine there). In the Drum Editor, loops appear and are placed, in track information lanes. In the MIDI Graphic Editor they go in the marker strip just beneath the time ruler, and only loops for the track you're currently editing (indicated by the little pencil icon in the Track Selector list) are shown.

One last thing: don't get fooled by the Track Overview's Loop column. This doesn't actually do anything except indicate the presence of a loop in a track, so trying to click or drag the little icons that appear is a fruitless exercise.

Get Real

The nature of DP's loop function is such that loop repetitions are 'live' copies of the source material they're generated from — so if you edit the loop source, all the repetitions instantly update to reflect that. That's great, until you want to make changes to some of the repetitions and find it's just not possible. An example of this might be when you want one drum pattern to run for most of your sequence, but have fills and little variations in several places.

Repeating data makes 'real' copies that can be edited individually without affecting the other copies.In this case, a better alternative to the loop tool is to actually duplicate your loop source material multiple times, resulting in a track full of data but all of it independently editable. DP has some functions that exist specifically for this task. Let's look at a practical scenario, with a one-measure MIDI drum pattern that needs to be extended to fill up a 32-measure section of the sequence, ready for further editing.

In a MIDI editing window (which can be the Tracks Overview this time), drag the I-Beam tool over your drum pattern, with a suitable edit resolution grid in place, to precisely time-range-select the pattern. Now hit Apple-R, or choose Repeat from the Edit menu. In the dialogue box that appears, choose Merge or Paste (we'll discuss what these options do in a minute), and set the number of repetitions to 31. They'll be added after the original pattern, to make 32 measures in total (see screenshot overleaf). Click OK to finish the process.

So what are those 'Place copies...' options in the dialogue box all about? Well, Splice inserts the repeats into the track, and shoves along pre-existing data that follows them by the same amount. Paste and Merge don't do any shoving, but whereas Merge blends anything already in the track with the repeated data, Paste overwrites it. There's another subtle distinction between Paste and Merge: If the original time-range selection included MIDI data starting inside but finishing outside the selection region, repeating with Merge will ensure that they're correctly handled in the repeats too. Paste's approach is to truncate those events — a subtle but sometimes crucial distinction.

Filling A Gap

The Repeat command painlessly handles most straightforward musical situations, but is less good if you happen to be working on complex, polyrhythmic or 'free time' material that doesn't align so easily with beat and measure boundaries. Say you want to make a 'shimmering' effect with a harp-like synth sound, and fill up a four-measure section with a rapid, arpeggiator-like pattern of 32nd notes. While you could certainly try to use Repeat for this, you have a problem in that you don't know how many repetitions will be required to fill up the eight measures — at least, not without whipping out your calculator and doing some fiendish division. This is where the Merge Repeat and Paste Repeat functions come into their own. Let's see how they work, using exactly the scenario I just described.

The Paste Repeat command has been used here to fill a four-measure region with a rapid three-note pattern, in a single stroke. 1. First, in the Sequence Editor, select the pattern to be repeated in the synth harp track.

2. Hit Apple-C to copy the data.

3. Now make a time-range selection of the region of the synth harp track to be be filled with the pattern, which should also include the original pattern notes.

4. Choose Paste Repeat from the Edit menu. The entire region should now be filled with the pattern. If there's a partially empty measure at the end of the section, it's because DP won't paste a partial pattern when one final whole pattern won't fit into the region. In which case, just do a quick additional cut and paste (or alt-drag) of the pattern manually, to fill up the space.

Using Paste Repeat rather than Merge Repeat in this example is better, because it ends up overwriting the notes of the original pattern within the region, ensuring you don't get duplicated MIDI events. But Merge is there when you need to add a repeated phrase to existing data in the track.