A change of pace

Often, you’ll want to change the tempo or pitch of a loop to make it fit with other elements of a track as we have shown in the tutorials. This can work by resampling and granular processing. Resampling works much like speeding up or slowing down a tape machine or vinyl record player. The tempo and pitch are linked, so the slower the audio data is played back, the lower in pitch it becomes, and the faster it’s played back, the higher in pitch it rises. The advantage of this method is that it’s quick and easy for software to perform, and it usually maintains the transients and texture of the audio well.

Frequently, though, it’s beneficial to be able to control the tempo and pitch of a sound independently, and this is where granular processing (often known in this context as ‘warping’) comes into play. By slicing the audio into thousands of tiny sections and duplicating or removing them as necessary, it’s possible to make an audio clip much longer or shorter – a technique known as timestretching. And when combined with resampling, it can also be used to change the pitch of the audio – that’s pitchshifting. The catch is that this process is more likely to have an impact on the quality of the audio, which is why most DAWs and samplers offer a choice of granular processing or warping algorithms. Some algorithms will work better with beats, others with pitched ‘musical’ material or vocals, so it’s worth getting to know all of your software’s available algorithms to find out which are best suited to particular tasks.

Another way in which DAWs and samplers can be used to change the tempo of loops is by slicing them into individual beats, which can then be played back faster or slower. This technique preserves the pitch of the audio and leaves the loop’s transients unaffected, although it can sound unnatural if the loop features longer sounds such as ride cymbals. This slicing information can be stored in formats like Acidized WAV, Apple Loops (AIF) and REX (RX2) file formats, automatically adjusting imported audio in any of these formats to fit your project’s tempo.

Most of these formats were influenced by the mother of loop slicers, Propellerheads ReCycle (amazingly still available from www.

reasonstudios.com for £89). It is a venerable piece of software for slicing loops and exporting RX2 files. These days, though, most DAWs and samplers can slice loops into sections and create sampler patches and

MIDI timing sequences automatically, so it’s worth investigating your DAW’s slicing abilities to see what it’s capable of.