Distortion is a gain effect used in amplified music achieved by overloading the input. The result is a compressed sound that people often describe as warm and dirty. Distortion has, in many ways, strongly influenced modern music, starting with the “electric guitar revolution” of the 1950s. The character depends upon the type and intensity of distortion. Technically, any added content to a signal represents distortion. However, in audio production, it usually refers to some overload.
Types of Distortion
Out of the many implementations of distortion, I will exemplify those most responsible for shaping the sound of guitar and electronic music today.
Saturation & Clipping
Most VSTs that feature this type of distortion imitate tape machine analog effects – known to provide a certain sense of warmth to the sound. Also, there is a hint of compression or narrowing of the dynamic range.
An effect of medium-strength, emulating a vacuum tube or solid-state transistor amp circuit. It produces a slightly heavier amount of saturation compared to Clipping.
Overdrive & Fuzz
These are quite desirable implementations of distortion. Overdrive is just a little less extreme than Fuzz. Both are predominantly applied to guitar, but they may be used on any instrument. Additionally, Fuzz generates a more self-evident, “screaming” effect than overdrive.
This type of distortion – unlike the previous types – exists solely in the digital realm. It results from periodic quantization error and/or aliasing. This means the computer does not have a great enough bit depth and/or sample rate to rectify the signal, so it rounds off samples to the nearest value determined by the resolution parameters on the bit crusher. This process causes a low-fi, sometimes robotic sound that is quite desirable in modern electronic music. It is the audio equivalent of what would happen if you were to play a 1080P video on a monitor that only supports up to 720P.
I usually use a bit crusher on drum loops because it accentuates the distorted high-frequency content.
TECHNIQUES & TIPS
Using harmonic distortion to make something more clear (although it sounds contradictory) is an excellent approach. Believe it or not, small amounts of harmonic distortion can make harmonics more evident. For example, this trumpet sounds more like a real trumpet after emphasizing it’s upper partials.
Another great way to use distortion is on vocals. A good option is to duplicate the original vocal track and add distortion to the duplicate (in parallel). This way, the original vocal characteristics remain pure, yet, the sum contains some interesting added harmonic content. Accompanied by a bit of reverb, EQ, and compression, the end result sounds AWESOME.
In conclusion, from extremes like Fuzz & Bit crushing to more subtle options like tape-saturation, distortion is effectual. You can apply it to just about any audio source, and it can really morph your sound into something truly amazing.