Separating noise from other elements
IN RECENT YEARS we’ve seen a rise in software tools that let us separate noise – ie unpitched elements of a sound – from tonal elements. RipX, from Hit’n’Mix, is one such application. This uses machine learning in order to separate the two elements of a source sound. This has obvious uses for mixing and post production, making it easy to remove unwanted noise from a poor quality recording, say. But it can also be used creatively, for example by boosting noise elements in a sound to unnatural levels in order to bring out unique character.
Possibly our favourite tools in this realm are Bitwig Studio’s suite of Spectral Effects. Unlike tools like RipX, which generally work offline – ie they analyse and then separately output the pitched and unpitched elements – Bitwig’s spectral tools are splitters that allow for ‘live’ processing of different elements of an audio feed. These tools can split sound in various ways, including separating different frequency bands and loud versus quiet elements. When it comes to working with noise, however, there are two Spectral Effect devices of note.
The first of these is the Transient Split device, which allows users to separately process the percussive transients and tonal body of a sound. Broadly speaking, when it comes to drums and percussion, it’s the transient elements that tend to be more noise-like, while the body – particularly in the case of kicks and snares – often has a more defined pitch. As well as adjusting the balance of these elements, the Spectral
Effect devices allow for individual effect chains to be applied to each. There’s no end of ways to be creative with this, but one particularly appealing technique is to apply creative reverb or delay just to the noise-based transient elements of a sound.
Similar in scope is
Bitwig’s Harmonic Split device. This divides an incoming signal into odd and even harmonic feeds, but also has a third output for non-harmonic sounds. This can be fun for isolating the noise elements and extracting them from a more complex loop – a low-quality vinyl sample, for example – or distorting just the nonharmonic noise elements of a sound.