Distortion and fuzz

What it is and how it works

Distortion: hard clipping obtained with diodes to ground or high-gain stages. The waveform is cut almost flat: many odd harmonics, compressed sound, long sustain, reduced dynamics. Reference pedals: ProCo RAT, Boss DS-1, MXR Distortion+; high-gain amp channels (Mesa Boogie, 5150, modified Marshalls).
Fuzz: extreme clipping, often with transistors (germanium or silicon) in simple configurations that turn the wave into something close to a square wave. "Woolly," saturated sound, with a characteristic decay and sometimes gating (the sound "breaks up" at the end of the note). References: Maestro FZ-1 (1960s), Dallas Arbiter Fuzz Face, Electro-Harmonix Big Muff (multiple clipping stages and a tone control with a mid scoop around 1 kHz), Octavia (fuzz with rectification, adds the octave above).
Rectification (rectify): half-wave (cuts one half-wave) or full-wave (flips the negative ones): full-wave doubles the perceived frequency (octave above).
Extreme bit and waveshaping: drawn curves (Fruity WaveShaper), "sincrush", "cube": synthetic distortions.

Gain / Distortion / Fuzz: amount of clipping.
Tone / Filter: indispensable; in heavy distortion the sound immediately becomes harsh.
Pre-EQ: cuts bass before (a "tighter" sound, less mud, typical of modern metal: HP 100–150 Hz before the gain) and sometimes emphasizes the mids (TS-style boost).
Bias (fuzz): shifts the transistor's operating point: "starved" bias = broken, gated sound.
Gate: high-gain distortions raise hiss and hum: noise gate before and/or after.
Mix: parallel to keep the clean signal (bass, vocals, drums).
Oversampling: indispensable to avoid aliasing (metallic non-harmonic sounds) on heavy distortions.

Distructor: 4 slots; Harmor (Classic, Flathat, Cube, Log, Softsat, Rubber, Ribbon, Sincrush, Bitcrush, Bitjam), Distructor (Wave folder, Aperture, Abrasive), Crusher, Blood Overdrive, Soft Clipper models; plus Filter, Chorus and AMP/CAB to simulate amp and cabinet.
Hardcore: guitar multi-effect (distortion and fuzz pedals, amp, cab).
Fruity Fast Dist (simple distortion), Fruity WaveShaper (free curve: hard clip, foldback, rectification), Effector DISTORT (Amount and Tone), Fruity Blood Overdrive with x100.
Third party: FabFilter Saturn 2, iZotope Trash, Soundtoys Decapitator (Punish) and Devil-Loc, Kilohearts Distortion, Guitar Rig, Amplitube, Neural DSP, Big Muff/Fuzz emulations by Arturia and Electro-Harmonix.

Rock and metal guitars: amp distortion, double-tracked L/R (two different takes left and right, not the same one copied).
Metal/industrial bass: distorted parallel path (HP 200–400 Hz) on top of a clean or compressed bass.
Synth leads and bass (dubstep, industrial, hyperpop): distortion as sound design, often with multiple stages and filters between one instance and the next.
Drums: distorted drum bus in parallel (industrial, experimental hip hop), "crushed" snares.
Vocals: distortion for effects (industrial, nu metal, hyperpop), always filtered and often in parallel with the clean vocal.
Fuzz: psychedelic and stoner guitars, garage basses, "dirty" synths.

Use	Type	Pre-EQ	Post-EQ	Mix
Metal rhythm guitar	high gain + cab	HP 100–150 Hz, boost 700 Hz–1 kHz (TS)	HP 80 Hz, LP 9–11 kHz, −2 dB at 3–4 kHz if harsh	100%
Stoner fuzz guitar	fuzz (Big Muff)	—	mids to restore (+2 dB at 800 Hz–1.2 kHz)	100%
Metal bass	distortion on parallel path	HP 250–400 Hz	LP 5–6 kHz	20–40%
Industrial synth lead	Distructor 2 slots (distortion + filter)	LP first for less fizz	−3 dB at 3–6 kHz	100%
Industrial drum bus	hard clip/distortion	HP 100 Hz on the path	LP 10 kHz	15–30%
Effect vocals	distortion + band-pass	BP 300 Hz–4 kHz	de-esser	20–50%

Metal (djent, metalcore): very filtered high-gain distortion, tight gate, quad-tracked guitars.
Rock/stoner/psychedelia: fuzz and vintage distortions.
Industrial, EBM, hyperpop, rage: distortion on everything (vocals and 808 too) as an aesthetic.
Dubstep, riddim: chains of distortions and multiband for basses that "talk".

Too much gain: small, compressed sound, guitars you can't make out (in metal you use less gain than you'd think).
No filter: fizz and mud.
Doubling with the same take copied L/R: sounds mono and unnatural (use two different takes).
Aliasing: distortions without oversampling that "whistle" on high notes.
Distortion on vocals without parallel: loss of intelligibility.

On a guitar: raise the gain until the individual notes of a chord can no longer be told apart, then back off by a third.
With a sine tone the 3rd and 5th harmonics rise a lot: it is the signature of hard clipping.
Turn oversampling on and off on a high note of a distorted lead: you hear the inharmonic whistles disappear.

Parameter	Value	Why
Gain	Less than it seems necessary	Note definition.
Pre-HP	100–150 Hz (guitar), 250–400 Hz (bass parallel path)	Tight distortion.
Post-LP	8–11 kHz	Removes the fizz.
Gate	Before and/or after, threshold above the hiss	Silence between riffs.
Oversampling	4–8×	No aliasing.
Mix on bass/vocals/drums	15–50%	Clean signal preserved.

Range	What to do
Below 100–150 Hz	Cut before the distortion for a tight sound without mud.
700 Hz–1.2 kHz	Mids that define the distorted guitar; a Big Muff-type fuzz scoops them out.
2–5 kHz	Bite and harshness: control with post EQ.
Above 8–10 kHz	Fizz and aliasing: LP and oversampling.

Step	Tool	Settings	Why
Input gate	Fruity Limiter (Noise Gate) / Pro-G	Above the noise	Less hiss before the gain.
Pre-EQ / boost	Fruity Parametric EQ 2 / TS emulation	HP 120 Hz, boost 700 Hz–1 kHz	Tight, defined distortion.
Distortion/fuzz	Distructor / Hardcore / Saturn 2 / Trash / Guitar Rig / Neural DSP	Medium gain, oversampling	Character.
Cab / IR	Distructor AMP/CAB / Fruity Convolver with cabinet IR	4x12 or 1x12	Shapes the response like a real speaker.
Post EQ	Fruity Parametric EQ 2	HP 80 Hz, LP 10 kHz, −2 dB at 3–4 kHz	Fits into the mix.
Light compression / bus	Fruity Compressor / guitar bus	GR 1–2 dB	Cohesion.

Spectrum of the distorted guitar: energy concentrated at 100 Hz–6 kHz, attenuated below 80 Hz and above 11 kHz.
Very low crest factor (4–7 dB) on distorted guitars: normal; don't compress them further.
Correlation of the doubled L/R guitars: between 0 and +0.5 (two different takes), never close to +1 (copy) nor negative.
No evident inharmonic component above 10 kHz on high notes (aliasing).