Making Music
  Computer Music Software and Hardware

It's all about timing

At one time or another you will almost certainly discover a perfect loop that plays at the wrong tempo for your song.

The most obvious way to change a drum loop's tempo is to time stretch it. To make it play slower, you time stretch it or increase the length of the sample. To make it play faster you time compress or shrink it. This works fine although the sample is, of necessity, processed, both to change its duration and to preserve its pitch. There is another way to change tempo without any processing at all and that's to use our friend the beat slicer.

When a loop has been divided into slices you can load it into a sequencer and change its tempo simply by changing the sequencer's tempo. If that sounds a bit implausible, let's run through a simple example. Let's say you have in a sequencer a four-to-the-floor one-bar sample consisting of four bass drum hits on each quarter beat of the bar. No matter how far you crank up the sequencer's tempo, the sample is will still be triggered once and will play for its allotted duration.

However, if you cut the sample into four and increase the tempo, the four hits will play faster because each one is being triggered more quickly - instant tempo change! You can easily try this for yourself by loading a sample loop into your sequencer then cutting it into segments and changing the tempo.

I've started so I'll finish

Of course, this is a simple example and a rather rough way to go about it. With a more complex loop, if you crank the tempo up too high, the start of one slice will begin before the previous one has finished.

If you slow down the tempo there will be gaps in-between the slices. But as long as the tempo is not changed by a radical amount, there should be no problems. However, to help in situations where you want to decrease the tempo, ReCycle has a stretch function which extends the tails of the hits to fill up the gaps.

Some slicers can export files in formats directly compatible with a range of software. BeatCreator can save loops in several formats including SoundFont, LM•4, FruityLoops, Mixman and, for loop creators, the all-important REX file format.

Good boy, REX With the release of ReCycle, Steinberg created a new file format called REX which is essentially a sample loop cut up into slices by ReCycle. You can load REX files into a sequencer and the loop will correctly play at any tempo you select, within reason. You can open REX files in Propellerhead's Reason, principally in the Dr. Rex module designed to process and play REX files. A growing number of audio software sequencers and editors supports the REX file format and many sample CDs include REX files so you can take advantage of the format without owning ReCycle or doing your own carving.

REX files can be loaded into a sequencer (providing it supports the format) and then you can freely alter the tempo and the drum pattern will change with it. It's much like using MIDI parts.

In fact, both BeatCreator and ReCycle can export a MIDI pattern to play the REX samples so you can change the order in which the samples play by changing the MIDI notes in your sequencer. And if you quantise the MIDI part, you also quantise the audio. If your sequencer has a quantise audio function you'll be able to quantise the audio slices directly to create a swing feel, for example.

A moving experience

Another benefit of REX files is the ease with which slices can be moved around. The sample in one slice can quickly be swapped for another sample, although this is often easier in a dedicated beat slicer if you're still experimenting with the pattern.

But in a sequencer, you can drag individual slices onto different audio tracks. This enables you to do several interesting things. For example, you can pan slices to different positions in the stereo image, even creating dynamic pan effects either with an effect or using your sequencer's mixer automation function.

Individual slices can be processed on a track-by-track basis or in groups as you run them through the sequencer's mixer. It's amazing how much difference a little EQ can make to the tone of a drum.

For a really down and dirty track, add a dash of distortion. For special effects, add echo to a hit. Try letting the echo run on as the rest of the loop plays, and try cutting it short at the end of the hit. Compare the two versions.

It's easy to remove slices, substitute one sample slice for another, and you can double up on hits by placing an additional snare slice, for example, on a track so it plays at the same time as the kick drum. This is a quick and convenient way to create the range of drum loop variations that you need for a song.

One trick to enhance or beef-up a hit is to add a synth part to it which you can do by placing a note on a MIDI track at the same position as the hit and played by a soft synth. Add a low-pitched bass sound to beef up a kick drum or tom, or add gentle bells to an agogo run around the kit.

The technological drum

Finally, in your search for drum loop variety, let technology help. There are now several programs that create and manipulate loops in all manner of weird and wonderful ways. We've already mentioned several including Intakt which can slice and perform myriad loop manipulations, too.

Check out Steinberg's Xphraze which can not only create drum patterns but also bass lines, arpeggios and melodic riffs, too. And take a look at Groove Agent and BeatBurner.

Some purists might argue the case against the use of such software and that's their prerogative but then some folks were against CDs and now their vinyl is warped and twisted.

The technology is there to help you make totally new loops from the vibrations of virtual reality, and to manipulate and process existing samples and loops and mould them to your musical vision.