Grinding Discs — User Manual, Physical Modeling Engine & Sound Guide

1. Welcome to a Completely Ridiculous Plugin

Let’s be honest right from page one: Grinding Discs is a thoroughly absurd idea for an audio plugin. Nobody sits down to produce a track and thinks, "You know what this song is missing? Sixteen motorised slabs of cast iron, rubber, bone, sandstone, and glass clamped onto a metal axle and forced to grind against each other until they glow red-hot."

And yet… the moment you slow a few glass and bronze discs down to a gentle crawl, add a drop of lubrication, and tune them to a musical scale, something magical comes out of your speakers. Because real stick-slip friction is the exact same physical force that makes a wet finger sing on the rim of a wine glass, a cello bow bite into a string, a heavy vault door groan, or rusty train brakes scream, this contraption is a goldmine for evolving drones, bowed glass pads, horror soundscapes, clockwork rhythms, and sympathetic audio resonance.

Grinding Discs: Vintage workshop console featuring real-time 3D thermal/spark chamber, 30-material workstation, axial oscillator, coolant steam physics, and dual Art Deco VU meters.

🚫 100% Sample-Free

Zero recorded .wav files, loops, Foley clips, or sampled IRs. Every creak, chime, spark, and enclosure reflection is synthesized live.

⚙️ Up to 16 Spinning Discs

Stack 2 to 16 discs spinning clockwise or counter-clockwise with independent RPM, clamping force, lubrication, pitch, Q, and up to 48 notched teeth.

🧪 30 Physical Materials

From singing Crystal, Glass, and Bronze to Rubber, Bone, Millstone, Cast Iron, Diamond, Tape, and physical Air Gap isolators.

🎛 Generator + Insert FX

Spin the motor on an empty track for endless generative drones, or feed external drums, synths, and guitars through the tuned modal stack.

2. Zero Samples — Everything Happens Live

Pure Physical Modeling Signal Flow

Because nothing is pre-recorded, no two moments ever repeat in a loop, and every micro-movement on a knob reacts immediately like a physical workshop machine:

Stick-Slip Contact Friction: Adjacent discs continuously grip and release against one another based on relative RPM, normal clamping force (0–100 N), oil lubrication, and surface roughness.

Rim Topography & Notched Teeth: Smooth rims (0 teeth) bow continuous singing tones; milling up to 48 teeth across 9 geometric profiles generates clockwork clicks, buzzes, and polyrhythmic chatter.

30-Material Modal Resonator Bank & External Audio Input: Friction energy—plus any external DAW audio fed into INPUT LEVEL—excites multi-mode resonant filter banks quantized to 7 musical and microtonal scales.

Thermodynamics, Abrasive Wear & Coolant Steam: Rubbing builds real-time heat (°C) that subtly drifts modal tuning. Pouring COOLANT wets dry interfaces and sizzles into steam when discs run hot.

Chassis Frame & Synthesized Acoustic Enclosures: Vibrations couple into 4 structural chassis bodies and 6 synthesized workshop/horn/tank spaces before dual-VU stereo monitoring and safety limiting.

3. The 3D Viewing Window

Upper-center 3D wooden chamber with caliper selection indicators, glowing friction seams, spark particles, and live telemetry bar.

Click Any Disc to Edit: Click directly on any disc in the 3D stack to select it. Yellow caliper arrows highlight the active slot, displaying its index and material on the left (e.g. D1 · WOOD) and live rotational speed on the right (60 RPM).
Top Telemetry Bar: Displays active disc count, axial oscillation state (OSC), dissipated friction power (Watts), peak surface temperature (°C), and interface clamping force (N).
Thermal Glow & Sparks: High pressure and speed cause contact seams to glow warm amber, bright orange, and white-hot while ejecting live spark particles.
Air Gap Visualization: Slots assigned to Air Gap appear as open axle spacing, mechanically isolating upper and lower disc sub-stacks.

4. Disc & Contact Workstation (Center Panel)

Center Workstation: D1–D16 selector tabs, 30 material buttons, 10 per-disc/interface knobs, the Big Red Motor Button, Harmonic Tune, and Preset Manager.

Selecting & Managing Discs

D1 – D16 Tabs: Jump directly to any disc in the stack (up to 16 discs total).
- DISC / + DISC & + SPACE: Remove or append discs, or insert an Air Gap isolator so neighboring groups stop rubbing across that slot.
SPINNING Toggle: Starts or parks only the selected disc. Leaving one disc parked stationary while its neighbor spins against it acts like an endless violin bow!

The 30 Physical Materials

Warm & Organic

WOOD, BAKELITE (Plastic), RUBBER, BONE, LEATHER, TAPE

Woody creaks, muted rawhide rasps, hollow bone taps, and deep rubber stick-slip honks.

Singing & Tonal

GLASS, CRYSTAL, MUSIC BOX, BRASS, BRONZE, COPPER, CERAMIC

Long, pure modal sustain—from wine-glass rims and crystal bowls to temple bells and steel tines.

Heavy & Gritty

SLATE, EMERY, CARBORUNDUM, WHETSTONE, MILLSTONE, SANDSTONE, BASALT, OBSIDIAN

Coarse mineral abrasion, tectonic low-end rumbles, razor-honing hiss, and volcanic glass grit.

Metallic & Industrial

STEEL, CAST IRON, TITANIUM, DIAMOND, CARBON, GRAPHITE, FERRITE, VINYL

Bright metallic screech, foundry machine resonance, crystalline cutting-wheel whine, and shellac crackle.

Mechanical Isolator

AIR GAP (+ SPACE)

Opens physical empty space on the spindle so discs above and below do not rub against each other.

The 10 Per-Disc Controls & Big Red Button

Speed, Pressure & Tone (Top Row): SPEED (-800 to +800 RPM — counter-rotating neighbors double relative rubbing velocity), PRESSURE (0–100 N), LUBRICAT. (0–100% oil film), PITCH (HZ) (20–4000 Hz), and Q-FACTOR (1–1000 ring time).
Surface Texture & Teeth (Bottom Row): TEETH (0–48 rim notches), DEPTH, STYLE (Spikes, Cogs, Sawtooth, Pins, Chisel, Fluted, Crown, Serrated, Lobes), ROUGHNESS, and VAR DRIFT.
The Big Red Button (Machine ON / OFF): Master power switch for the drive motor. Cutting power mid-phrase lets the heavy stack coast and screech organically to a halt.
Bottom Utility Bar: ALL RANDOM generates fresh machines (respecting front-panel PIN locks), # HARMONIC TUNE quantizes every disc to the chosen musical scale, and LOAD / SAVE PRESET manages the 11 factory archetypes and custom user JSON patches.

5. Left & Right Console Wings

Left Wing — Drive, Axial Oscillator & Input

Main Drive Engine: Master SPIN ALL, macro SPEED (0–200%), and organic VAR SPEED / VAR DEPTH motor flutter.
Axial Oscillator: Reciprocates the stack along the spindle using Sine, Triangle, Sawtooth, Square, Rand S&H, or Chaos shapes.
Input, Stereo & Wear: Stereo WIDTH, 7-mode SCALE selector, long-term abrasive WEAR, and INPUT LEVEL (with PIN lock) for routing DAW audio into the discs, plus Left Analog VU Meter (CH. A).

Right Wing — Thermal, Enclosures & Output

Acoustic Focus & Thermal: Root FOCUS (HZ), STACK COUNT (2–16), liquid COOLANT (with hot-disc steam sizzle), and HEAT RATE.
Space & Chassis: 6 enclosures (Cast Iron Bed, Steel Boiler, Forge Workshop, 55-Gal Oil Drum, Brass Horn, Ceramic Kiln) and 4 chassis frames with ROOM SIZE and DAMPING.
Mix & Output: Separate FRICTION MIX, BODY MIX, and CONV MIX, plus PIN-lockable DRY / WET and OUTPUT LEVEL above Right Analog VU Meter (CH. B).

6. Four Quick Sound Design Recipes

In addition to the 11 built-in factory presets (including Bowed Glass & Crystal Singing Bowls, Heavy Freight Train Brake Squeal, Japanese Timber Workshop, and White Hot Thermodynamic Forge), try these starting points:

Ambient / Bowed Pad

Recipe 1: Hypnotic Singing-Bowl Drone

Empty Track Generator (Dry/Wet 100%)

Slow-moving glass, crystal, and bronze rims singing in pure harmonic intervals without a single static loop.

Stack: Stack Count: 4 • Materials: Glass, Crystal, Bronze, Copper

Discs: Teeth: 0 (Smooth) • Q-Factor: 320+ • Pressure: 18 N • Lubrication: 40%

Tuning / Mod: Scale: Just Intonation or Gamelan Pelog -> Click # HARMONIC TUNE

Global / Space: Global Speed: 25% • Coolant: 20% • Space: Ceramic Kiln (35%)

Cinematic / Foley

Recipe 2: Creepy Horror / Sci-Fi Vault Groans

Empty Track Generator -> Automate Big Red Button

Massive subterranean metallic groans and freight-brake screeches with dramatic mechanical wind-downs.

Stack: Stack Count: 6 • Materials: Cast Iron, Millstone, Rubber, Basalt

Discs: Pitch: 35–90 Hz • Pressure: 75+ N • Lubrication: 5% (Dry)

Tuning / Mod: Axial Oscillate: ON (Chaos shape, 0.35 Hz, 70% Depth)

Global / Space: Global Speed: 15% • Space: Steel Boiler (45%) • Cut Big Red Button mid-take!

Rhythmic / Industrial

Recipe 3: Rusty Clockwork Polyrhythm

Generator or Parallel Drum Layer

Interlocking cogwheels and music-box pins clicking in polyrhythmic mechanical patterns inside a wooden coffer.

Stack: Stack Count: 5 • Materials: Music Box, Steel, Wood, Bakelite

Discs: Teeth Counts: 7, 12, 16, 24 • Tooth Style: Pins & Cogs • Depth: 75%

Tuning / Mod: Scale: Equal Temperament -> Click # HARMONIC TUNE

Global / Space: Chassis: Wooden Soundbox (Body Mix 55%) • Stereo Width: 120%

Insert FX / Resonator

Recipe 4: Sympathetic Resonator on Drums or Synths

Audio Insert on Drums, Guitar, or Synth

Uses stationary tuned discs as a physical modal resonator bank excited purely by incoming track transients.

Stack: Big Red Button: OFF (Stationary Stack) • Materials: Glass, Brass, Titanium, Bone

Discs: Q-Factor: 180–450 • Focus (Hz): Match track key root

Tuning / Mod: Click # HARMONIC TUNE to lock discs to your song's scale

Global / Space: Input Level: Raise until PEAK glows • Dry/Wet Mix: 30–40%

7. Platform Installation & Apple Logic Pro Notes

Linux (x86_64 — CLAP & VST3)

Copy grinding_discs.clap to ~/.clap/ or copy the grinding_discs.vst3 folder to ~/.vst3/. User presets are stored in ~/.local/share/grinding-discs/presets/.

Windows (64-bit x86_64 — CLAP & VST3)

Copy grinding_discs.clap to C:\Program Files\Common Files\CLAP\ or grinding_discs.vst3 to C:\Program Files\Common Files\VST3\. User presets live in %APPDATA%\grinding-discs\presets\.

macOS Universal2 (Apple Silicon & Intel — Logic Pro AUv2 & CLAP)

Copy Grinding Discs.component to /Library/Audio/Plug-Ins/Components/ (for Logic Pro, GarageBand & MainStage under Audio Units → vanBuffelen → Grinding Discs) and/or Grinding Discs.clap to /Library/Audio/Plug-Ins/CLAP/. If macOS Gatekeeper flags the ad-hoc signed bundle on first launch, run:
xattr -cr "/Library/Audio/Plug-Ins/Components/Grinding Discs.component"
Logic Pro Keystroke Tip: Because Logic Pro intercepts computer keys for DAW transport shortcuts, Grinding Discs automatically pops up a built-in mouse-clickable On-Screen QWERTY Keyboard whenever you name or save a preset.

8. Complete Parameter Reference Table

Search and filter all global, per-disc (D1–D16), and per-interface (I1–I15) parameters:

ID	Name	Module	Type	Default	Range / Values	Unit	Description
`motor_active`	Motor Run / Spin All	Drive	Toggle / Big Red Button	`On`	Off / On	—	Master motor power switch. Turning off cuts drive power so discs coast and grind naturally to a stop.
`global_speed`	Global Speed	Drive	Knob	`100%`	0% to 200%	%	Scales the rotational speed of the entire disc stack simultaneously.
`var_speed_enabled`	Variable Speed Enabled	Drive	Toggle	`Off`	Off / On	—	Engages organic motor wow, flutter, and speed drift across all spinning discs.
`var_speed_depth`	Variable Speed Depth	Drive	Knob	`55%`	0% to 100%	%	Global intensity of rotational speed drift when Variable Speed is enabled.
`osc_enabled`	Axial Oscillate	Oscillator	Toggle	`On`	Off / On	—	Pushes and pulls the disc stack cyclically along the central axle.
`osc_type`	Oscillation Shape	Oscillator	Enum	`Sine`	Sine, Triangle, Sawtooth, Square, Rand S&H, Chaos	—	Waveform controlling axial reciprocating motion and contact modulation.
`osc_rate`	Oscillation Rate	Oscillator	Knob	`1.2`	0.1 to 20.0	Hz	Speed of the axial reciprocating LFO.
`osc_depth`	Modulation Depth	Oscillator	Knob	`55%`	0% to 100%	%	Excursion depth of axial contact pressure and motion modulation.
`stack_count`	Stack Count	Stack	Stepper / Knob	`6`	2 to 16	discs	Total number of active discs mounted on the vertical spindle.
`global_freq_focus`	Frequency Focus	Stack	Knob	`350.0`	40.0 to 4000.0	Hz	Emphasizes a resonant frequency region and sets the root pitch for # HARMONIC TUNE.
`tuning_scale`	Modal Tuning Scale	Stack	Dropdown	`Equal Temperament`	Equal Temp, Just Intonation, Pythagorean, Gamelan Slendro, Gamelan Pelog, Bohlen-Pierce, Quarter-Tone	—	Musical or microtonal scale quantized across all discs when clicking # HARMONIC TUNE.
`coolant_amount`	Coolant / Wet Grinding	Thermal	Knob	`0%`	0% to 100%	%	Pours liquid coolant onto rubbing surfaces; softens harshness and sizzles into steam on hot discs.
`thermal_rate`	Heat Accumulation Rate	Thermal	Knob	`1.0x`	0.1x to 5.0x	x	Controls how rapidly mechanical friction heats up the discs and bends modal pitch.
`wear_amount`	Abrasive Wear	Thermal	Knob	`0%`	0% to 100%	%	Gradually polishes and wears down coarse surface asperities over time.
`chassis_type`	Chassis Body Type	Acoustics	Enum	`Off / Direct`	Off / Direct, Cast Iron Bed, Wooden Coffer, Brass Horn	—	Selects the structural frame resonance supporting the central spindle.
`chassis_mix`	Body Mix (Chassis)	Acoustics	Knob	`0%`	0% to 100%	%	Blend amount of structural chassis body resonance.
`conv_space`	Enclosure Space	Acoustics	Enum	`Off / Direct`	Off / Direct, Cast Iron Bed, Steel Boiler, Forge Workshop, 55-Gal Oil Drum, Brass Horn, Ceramic Kiln	—	Synthesized physical acoustic enclosure surrounding the machine (100% sample-free).
`conv_mix`	Conv Mix (Space)	Acoustics	Knob	`0%`	0% to 100%	%	Wet blend of the synthesized acoustic enclosure space.
`conv_size`	Room Size	Acoustics	Knob	`1.00x`	0.50x to 2.00x	x	Scales the physical dimensions of the selected enclosure space.
`conv_decay`	Damping / Decay	Acoustics	Knob	`1.00x`	0.20x to 2.50x	x	Adjusts high-frequency absorption and decay length of the enclosure.
`conv_predelay`	Enclosure Pre-Delay	Acoustics	Knob	`0.0`	0.0 to 50.0	ms	Initial reflection gap before enclosure reverberation.
`stereo_width`	Stereo Width	Master	Knob	`0%`	0% to 200%	%	Spreads individual discs and interfaces across the stereo field.
`input_gain`	Input Level	Master	Knob + PIN	`0.0`	-60.0 to +12.0	dB	Feeds external DAW track audio into the disc stack for sympathetic excitation. PIN locks against ALL RANDOM.
`dry_wet`	Friction Mix	Master	Knob	`100%`	0% to 100%	%	Direct signal level of the rubbing contact interfaces.
`master_mix`	Dry / Wet Mix	Master	Knob + PIN	`100%`	0% to 100%	%	Master blend between untouched DAW track input (0%) and Grinding Discs (100%). PIN locks against ALL RANDOM.
`output_gain`	Output Level	Master	Knob + PIN	`0.0`	-60.0 to +12.0	dB	Final master output trim ahead of safety limiting. PIN locks against ALL RANDOM.
`disc[1..16].material`	Disc Material	Per-Disc	30-Button Grid	`Varies`	30 Materials (Wood..Tape + Air Gap)	—	Selects modal resonance profile, density, hardness, and friction behavior of the disc.
`disc[1..16].spinning`	Disc Spin	Per-Disc	Toggle	`On`	Off / On	—	Starts or parks only the selected disc. Parking a disc against a spinning neighbor creates bowed drones.
`disc[1..16].rpm`	Disc Speed (RPM)	Per-Disc	Bipolar Knob	`±60..240`	-800 to +800	RPM	Rotational speed and direction (+ clockwise, - counter-clockwise).
`disc[1..16].pitch`	Disc Modal Pitch	Per-Disc	Knob	`160..720`	20.0 to 4000.0	Hz	Fundamental modal resonant frequency of the disc.
`disc[1..16].damping`	Disc Q-Factor	Per-Disc	Knob	`25.0`	1.0 to 1000.0	Q	Modal ring sustain (low Q = damped wood/stone thud; high Q = singing glass/bronze bell).
`disc[1..16].teeth_count`	Rim Teeth Count	Per-Disc	Knob	`0..36`	0 to 48	teeth	Number of mechanical notches milled around the disc rim (0 = completely smooth).
`disc[1..16].tooth_depth`	Tooth Depth	Per-Disc	Knob	`60%`	0% to 100%	%	Height and impact intensity of rim notches.
`disc[1..16].structure_type`	Tooth Style	Per-Disc	Enum	`Spikes`	Spikes, Cogs, Sawtooth, Pins, Chisel, Fluted, Crown, Serrated, Lobes	—	Geometric contour of the notched rim teeth.
`disc[1..16].top_roughness`	Surface Roughness	Per-Disc	Knob	`30%`	0% to 100%	%	Micro-asperity grit across upper/lower contact faces.
`disc[1..16].var_speed`	Per-Disc Var Drift	Per-Disc	Knob	`50%`	0% to 100%	%	Individual sensitivity to Variable Speed motor wobble.
`interface[1..15].force`	Clamping Pressure	Interface	Knob	`25.0`	0.0 to 100.0	N	Normal force squeezing Disc N against Disc N+1 (light = airy singing; heavy = dense groan & heat).
`interface[1..15].lubrication`	Lubrication	Interface	Knob	`15%`	0% to 100%	%	Oil film viscosity between adjacent discs, taming dry screech into smooth bowed sustain.

Grinding Discs — User Manual