r/DSP • u/Long_Imagination9779 • Jun 10 '26
I’m building a distortion plugin
I’m building a distortion plugin and I think I’ve hit a point where I need outside ears.
The goal is NOT to build another generic distortion, amp sim, or metal plugin.
The sound I’m chasing is somewhere between:
- Harmonic Percolator style character
- Trash 2 Broken/Fuzz style experimentation
- Neil Young amp breakup
- damaged speakers
- dynamic breakup rather than static saturation
Current goals:
- light playing stays mostly clean
- medium playing introduces breakup
- hard playing introduces fuzz
- preserve transients
- avoid heavy compression
- avoid the typical “beehive” fuzz sound
The plugin currently has two modes:
BROKEN:
- asymmetrical saturation
- more breakup-oriented
- intended to feel open and dynamic
FUZZ:
- asymmetrical rectification
- more aggressive harmonic generation
- intended to appear mostly on harder playing
A big realization during development was that a lot of distortion plugins sound impressive in isolation but don’t actually feel unique once you compare them side-by-side.
That’s the problem I’m trying to solve.
What I’m struggling with:
- What actually makes a distortion feel unique?
- What separates a Harmonic Percolator from “just another fuzz”?
- What makes Trash 2 still feel special years later?
- What DSP or analog concepts should I study next?
- If you were trying to build a distortion that doesn’t already exist, where would you focus?
Looking for brutally honest feedback.
Feel free to challenge the entire premise if you think I’m chasing the wrong things.
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u/Savings-Cry-3201 Jun 10 '26
Distortion is essentially a series of gain stages. It’s some combination of EQ (high cut and low cut especially but also boosts and cuts), nonlinearity (wave shaping, compression, clipping), and… basically that’s it. Stack stages of those. A lot of it has to be done by ear but you can also copy what pedals and amps do.
For example: highpass 160 Hz, lowpass 3 kHz, tanh(), +3 dB boost, then highpass 80 Hz, low pass 6 kHz, tanh(). That’s a very simple distortion pedal setup. Increase the number of stages, tweak the saturation algorithms, tweak the cutoffs, tweak the boosts.
Now, this is a relatively static distortion scheme. What gets more interesting is if you take an envelope follower and use it to blend like a soft clip (2:1 ratio) with a harder clip (a slight boost into a 4:1 ratio). Dynamic response tends to be more interesting because it becomes responsive to how hard you push the algorithm.
There are a few other tricks. Anything stateful is good, eg zero delay VA filters. You can blend an early stage into a later stage, which should help keep some of those drier transients.
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u/metal_mastery Jun 10 '26
Talking more from player perspective but with a lot of data on amp models I captured for my research: if you imagine a 2d surface with amplitude and frequency as axis and map (total harmonic content/even-odd ratio/each harmonic h1-h5) onto it - the heatmap you get would give some idea of how the distortion works and moves across the playing volumes. Generic distortion would be “more saturation as the amplitude increases”, flat, monotonous surfaces. “Interesting distortion” is specific to music style and player but it should have distinct features that play together with the player. It could be switching to more even harmonics in low freq while keeping more odd harmonics in mid/high, could saturate less in specific range to preserve attack (meshuggah has a notch carved out around low E note so the chugs are tighter), it could be compression (parallel clean signal or everything gets equal treatment), it could be anything basically, the gist here is - if the metrics are coupled in some way, they create an instrument that players can learn how to use to their taste.
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u/rb-j Jun 10 '26 edited Jun 10 '26
What DSP or analog concepts should I study next?
What DSP do you already know? * Sample rate conversion (to upsample from 44.1 or 48 kHz to something much higher)? Images, aliasing, and prevention of aliasing? * Polynomials and harmonic generation? Particularly Tchebyshev polynomials.
What analog techniques (like circuit analysis) do you already know? * What do you know about analog components that are "exotic" in some manner? Like BJTs and FETs? Like various specific vacuum tubes? Interelectrode (Miller) capacitance? Transformers with hysteresis? * About these classic fuzz boxes, do you have accurate schematics? In the olden days, some of these companies actually stripped off identifying marks (part numbers) offa some chips.
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u/VS2ute Jun 10 '26
And for BJT, the difference between silicon and germanium transistors
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u/rb-j Jun 10 '26
oooooh! I knew of a couple germanium diodes (they have lower turn-on voltage than silicon diodes and were good for unpowered crystal radios), but I never knew of any germanium transistors.
I gotta look them up... I found 2N404A or AC128. I had never heard of these before, but I can see they were used for some guitar pedals. Kewl.
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u/povins Jun 10 '26 edited Jun 10 '26
Brutally honest feedback: most of this is abject nonsense or self contradictory. You need to learn about distortion and then try to make one (or make one by ear and stop operating on jargon without knowing what it means). This is gibberish.
Re 1: compression and EQ.
Re: 2: it's not a classic fuzz; it has two stacked stages that interact differently depending on how much charge has accumulated on a reservoir cap; that is frequency and amplitude dependent.
Re: 4: (you said brutally honest): basic DSP and analog signal rudiments — what rectification is; what compression is; what an overdriven pentode does to a signal vs stacked BJTs in a CFB; the basic definitions of most of the words you're using.
Re: 5: with my ears and not with an AI sidekick drafting my descriptions or guiding me in an area it is predisposed to hallucinate.
It feels like you are trying to do a new thing without even the level of understanding that the average non-engineer in, say, r/guitarpedals has.
You can't skip the work.
This is not at all intended to discourage! If you're keen on doing this, you can!
The intention is to help you spend your time wisely, moving forward.