All About FX: Distortion

Distortion’s been around so long that even its originations are unclear. Ask a variety of engineers and you’re bound to get a bunch of different responses as to who the first musician to popularise distortion was. History aside, distortion comes in a wide variety of different forms, each with their own unique characteristics. In this article, we explore some of the more common types of distortion and how they work.

Reel tape recorder mechanism vintage detail objects.

Tape saturation

Back in the days of analogue recording, studio engineers had to really be careful about their levels when recording to tape. Too low and the machine’s ‘tape-hiss’ would be obvious, too loud and the track would run the risk of distorting (known as saturation).
Instead of ‘clipping’ the signal (like digital recording techniques do), analogue tape behaves a little differently. The distortion and compression acts in an uneven or ‘non-linear’ fashion and produces artifacts that (in the right circumstances) can be pleasant to the ear.
As a result of experimentation, audio engineers quickly realised the potential for tape saturation’s ability to add colour, warmth and punch to their mixes. Used in the right amounts, tape saturation can even ‘glue’ tracks together, and help engineers create bigger and louder mixes full of edge and character.
While we’ve seen a decrease in the popularity of analogue equipment like tape machines over the years, there are still a countless number of musicians and engineers who swear analogue is far from dead.

A typical analogue audio meter as found on old tape recorders with the needle in the red


Distortion occurs a little differently. When a waveform is overloaded into a circuit, the signal is ‘clipped’, resulting in a flattening of the peaks.
Distorting a signal causes the top and bottom of that waveform to square off or become ‘clipped’, which adds harmonics that were not present in the original signal. This effect is the basis for many types of distortion.
Depending on the circuit, different types of distortion can be produced. Tube distortion for instance (known as overdrive), is produced by transistor-based equipment and is often used by guitarists for its ability to subtly compress and add lower harmonics to a signal. Many refer to it as a ‘warm’ and pleasant type of distortion.
On the other hand, transistor clipping adds higher, odd harmonics without the compression. The result is a much harsher and grittier tone.
Bitcrushing is yet another form of digital distortion that has been popularised heavily by modern electronic music producers (think Skrillex’s screechy midrange synths). In a nutshell, it’s simply the process of reducing the accuracy of a digital signal’s sampling rate. Reducing a 24-bit resolution .wav file down to an 8-bit resolution file will result in a degraded sound that feels ‘aged’ (much like the sound produced from the old Sega Mega Drives or NES systems). Dedicated bitcrushers allow you to crank this effect to the point of no return and create sounds full of lo-fi artifacts.

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