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Analog vs. Digital Distortion in Music Production

Dec 22, 2023

We wouldn’t blindly apply EQ or compression, and the same goes for saturation and distortion, too. Learn the differences between analog and digital distortion types, and how each can be used to its fullest for better music production.

Analog vs. Digital Distortion in Music Production

Distortion comes in many shapes, types and colors. Understanding distortion in tapes, tubes, and transistors, and how distortion is related to waveshaping, clipping, and limiting—all these will help you understand how choosing different distortion options can serve different goals.

As the developers of more than a few distortion plugins, we’ll guide you through these different varieties and help you select the right type of distortion for whatever situation you’re facing in music production. Let’s turn up the heat!

What Does Distortion Do to a Sound?

We’re familiar with the sound of distortion, but, in technical terms, what is actually happening?

The introduction of distortion to a sine wave, in general, will create new harmonic content above the original signal’s frequency.

Distorted Sine Waves Resemble Square or Triangle Waves

If you take a sine wave and distort it, it will start to resemble something like a triangle or square wave. The exact shape will depend on the distortion type and its settings.

In the same way, if you take a square or triangle wave and view your signal in an oscilloscope, then run a low-pass filter to slowly reduce its cutoff, you’ll see the square or triangle shape slowly morph back into a sine wave as the cutoff approaches the note you’re playing.

Basic Digital Distortion – Waveshaping

Digital distortion, at its most basic form, is quite easy to carry out. Since digital audio works using numbers, and applying algorithms to those numbers, simulating a ‘clipping’ distortion is pretty simple – you just stop the audio waveform from reaching a certain level, keeping it stuck at a certain maximum amplitude.

We can represent that threshold of clipping – the amplitude that is not to be crossed – using something called a transfer function. This plots the output level (vertical) against input level (horizontal).

How Does a Transfer Function Work in Distortion?

When the transfer function is a straight diagonal line, it means the output matches the input and there’s no change. But as the top of the line starts to kink and flatten, that’s where our clipping distortion starts. With a flat line (pictured below), clipping is complete. With a gentler slope, we see something resembling compression on each wave cycle.

How Does a Transfer Function Work in Distortion

The digital waveshaper and its transfer function can be surprisingly versatile in the distortion tones they can create. But not to an extent that approaches analog distortion.

This transfer function should be quite familiar to those who’ve worked with many compressors – the transfer functions of a distortion and a compressor’s threshold and ratio plots are the same thing. And for good reason.

Distortion Meets Compression? And Limiting?

Fundamentally, the ways that distortion processes act are very similar to compression and limiting processes: an audio signal is restricted in its rise in level once it passes a certain level.

One difference between compression and distortion is that compressors usually act like this over longer time windows than a distortion processor. A gentler, more ‘gluing’ compressor doesn’t just act on individual cycles of a waveform.

Theoretically, very fast attack and release settings may get quick enough to catch individual cycles of low-frequency waves, and so a limiter or clipper plugin, when used more harshly than usually intended, can induce some heavy distortion.

Using the CLA-76 Compressor/Limiter with its signature fast settings, we can achieve some really interesting distorted tones. This effect is emphasized by the 1176’s famous “all-button” mode, or “British mode”.

CLA-76 Compressor/Limiter

The Best Plugins for Analog-style Distortion

Applying distortion to a signal within the digital domain merely changes the sequence of ones and zeros. Our understanding of analog distortion combined with continually improving modeling technology means that we can now emulate analog distortion relatively accurately. This gives us all of the reliability, value and flexibility of software along with the tone and character of hardware.

Waves Abbey Road J37 Tape was developed in collaboration with Abbey Road Studios, and is modeled on the all-valve analog Studer J37 machine. Try the plugin out for yourself and hear the warmth and glue it can add to individual tracks, busses, or even your entire mix.

Abbey Road J37 Tape

Similarly, the distortion that can be achieved with Waves BB Tubes is based upon the character of analog equipment. This time, a tube-based architecture is responsible for the hefty analog tones coming from the plugins’ output.

BB Tubes

For more of an all-round distortion solution, Waves Berzerk Distortion takes the science discussed in this article and applies it to a versatile, easy-to-use and sometimes destructive distortion package.

Berzerk Distortion

Much like analog hardware, there’s a whole world of faithfully modeled plugins on the market, that between them cover just about every possible scenario.

The Charm of Analog Distortion

So how does distortion actually look when we observe it – both analog and digital – under the oscilloscope and the frequency analyzer?

The archetypal image of distortion is what you’ll see below. A wave was too loud for the capacity of the equipment it went through, and so the equipment chopped off the top of the waveform that it couldn’t handle. In theory, it looks like this:

Basic analog clip

But analog audio is known for its imperfections, and when real circuits handle real waveforms, theory doesn’t easily match practice. A piece of equipment could distort in any way. More likely, your waveform will be recreated but not properly; or perhaps distortion is only experienced on one side of the audio waveform.

Analog distortion real ways

You might not be surprised to learn that distortion could, under certain circumstances, be frequency-conscious as well, affecting lower frequencies differently to high frequencies.

So there’s a lot of variety in analog distortion, and a big diversity in the sounds that can be achieved with different distortion sources.

The Lineage of Non-Linearity

Distortion in its original meaning gives us quite a simple definition: it’s any difference between the signal going into and coming out of a piece of equipment. This was useful back in the days when electronic devices only sent signals for communication, and the ideal was for them to remain as crystal clear as possible… but in a world where we want to change the signal, we need to refine what we mean by distortion.

Distortion as we know it today came from the act of overloading a piece of equipment – feeding a signal that’s too loud for it to deal with properly. In analog equipment, the result varies greatly and depends on the nature of the source signal, its level and of course the equipment itself. Generally, subtle overloading results in a slightly distorted signal which could be characterized as warm or full. Extreme overloading can cause the signal to crunch or break up entirely.

A History of Distortion in Six Tracks

In the 40s and 50s, this kind of overloading often came in the form of a guitar amplifier with a cooked fuse. Or in the case of “Rocket 88” by Jackie Brenston and his Delta Cats, a ripped amp woofer stuffed full of paper.

As the 50s went on, artists chased never-before heard tones and textures by modifying guitars and amplifiers or pushing them beyond their limits. These modifications often involved intentionally damaging equipment as Paul Burlison did in “The Train Kept A-Rollin” by the Johnny Burnette Trio.

The unique guitar sound of this record was achieved by unseating the vacuum tube of his amplifier. This style of unpredictable, noisy guitar texture was the sound of the moment, but not everyone had the resources to destroy a piece of equipment for the sake of one or two records.

It wasn’t until the 60s when a piece of equipment was developed solely to achieve this sound. Developed in 1962 off the back of a faulty preamp which was used in Grady Martin’s “The Fuzz,” the Gibson Maestro FZ-1 Fuzz-Tone was born. This meant guitarists could apply distortion to their signal at their own leisure, without damaging or altering their precious equipment.

The FZ-1 was one of the first commercially available distortion pedals, and its popularity was heightened by Keith Richards’ use of it on (I Can’t Get No) Satisfaction.

Other popular consumer-grade pedals included the Electro-Harmonix Big Muff Pi, which was used by the likes of Pink Floyd, Kiss and Frank Zappa.

The availability of these pedals paved the way for others to apply the sound in a range of genres, heavy metal being a prime example. The genre is now associated with powerful, brash distorted guitar and drum tones, in part thanks to the likes of Eddie Van Halen. His “brown sound” technique involved the use of a distortion pedal as well as cranking his amp level.

Over the years, the use of distortion has found its way into all manner of musical styles. From the unapologetically distorted nature of noise music, to the huge 808 kick drums of contemporary drill music.

Today, audio distortion is a fundamental component of music production and sound engineering. Whether you’re using it as a creative sound design tool, a mixing technique, or if you’re trying to avoid it altogether, it’s important to understand how it works and how you can harness it or control it to achieve your desired sound.