2 minute read

Basis in Engineering

Historically, the term “treatment” was used within electrical engineering to mean a modification imposed on an analogue signal — a continuous, electrical circuit whose current or charge we can modulate with inventive engineering.

Amplification and filtering are these “basic operations” performed on an analogue signal.

Until digital computers, such analogue “treatments” were the only way to manipulate a signal.

Analogue Signal Processing

This mechanical treatment of sound was made possible through classic radio-telecommunications signal processing:

  • time-domain audio filters
  • EQ (“equalization,” or filters in parallel)
  • compression
  • reverberation (filters in series)

Tape Machines

Significantly, reel-to-reel tape machines were commonly found in early radio and TV studios.

Tape, in addition to its main use as a recording medium, extended treatments into the realm of time and pitch manipulation, and the re-ordering or shuffling of sonic events.

Think about this: with tape, you not only can store an electro-magnetic signal but also you can slow the tape down, or run it backwards. When you change a reel’s speed, it also raises or lowers the pitch of your captured signal. When you run it backwards, you also reverse time’s flow and with it, a sound’s entire ADSR envelope (attack, decay, sustain, release) — first, its release runs backwards, followed by its sustain, decay, and finally its attack. With the ability to chop up little pieces of tape (called “splicing”) and reconnect them, small components of sound can be reordered, making elaborate sound collages possible. Such was the creative research of Pierre Schaeffer and his followers.

Digital Treatments Today

Today we continue to use digital emulation of these classic analogue techniques as basic and “pure” sonic treatments. We tend to create interest and variety by personalizing each method of manipulation, or by combining them, one after another, into a signal chain.

Not Sound FX

Perhaps it’s not enough simply to call a treatment a “sound effect.” People tend to think of “effects” (a.k.a., “FX”) as a layer of processing that somehow “enhances” the raw/dry sound source, or doesn’t alter its character much.

While a treatment can certainly provide this, we cannot limit ourselves to this naive definition. Each of these basic operations, separate or combined in some way, makes possible a limitless range of expressive signal processing that could entirely change the sonic character of our original sound sources!

We could invent wholly other sound worlds from a single, quite different, source. The composer Tristan Murail wrote about this problem of “merely effects,” urging composers to think of treatments as their own musical source material, as the foundation of an entirely new, expressive musical object on its own.

For example, if you use a distortion pedal on your guitar, listen for and try to shape the quality of the distortion itself. Do not “insist” on hearing the guitar through the distortion. If we insist on effects alone, surely we will never realize the full potential of the coupled, combined sound source and its treatments.

We’ll examine how some of these treatments work and how they sound using Reapter and, later this semester, MaxMSP.