hyperframes/plans/audio-fx-presets.md

Audio treatment presets — research and proposed catalog

Written 2026-08-09. The ask: voice carve turned a pile of effects into one understandable feature; what else can, using only the effects already shipped?

This is a research + design doc. Nothing here is built.

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1. The governing precedent

wiki/decisions/vst-studio-integration-cancelled.md is the most important prior art, and it is a warning. A VST spectral-carve integration was built to completion — 4-PR stack, published PyPI host — and then cancelled, because of its standing costs:

• a spawned WebSocket sidecar with its own lifecycle
• an external GPL repo with its own release cadence
• a non-bundled runtime dependency users had to install
• VST logic permanently in the render path, hard-failing renders on a missing plugin

Everything proposed here is the inverse of all four: preset values are data, and the adaptive scripts reuse analysis code that already ships. No new process, no new dependency, no new render-path failure mode. A preset that goes wrong produces a chain the author can see and edit in the rack — the same chain they could have built by hand.

That is the argument for doing this at all, and the bar any proposal here has to keep clearing.

What already exists, so this does not duplicate it

• skills/hyperframes-audio teaches the effect families and when to reach for each ("Reach for a family by the problem, not the name"), and documents carve. It contains no recipes and no named looks — it explains the why, and stops short of the one-click. This catalog is the complement, not a rewrite. It also already fixes the canonical order this doc adopts: "corrective filtering goes early, character in the middle, and a limiter last."
• carveBandsToChain() already proves the mechanism: an analysis produces an ordinary HfAudioFxChain, which the rack then owns like any other.
• Demand is real and internal. Cortex carries user asks for audio reprocessing for studio acoustics, voice loudness and gain boosting, and auto-enhance across scenes. Nobody has built a preset catalog for it.

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2. What consumer tools actually ship

Three distinct tiers, and only two are reachable for us.

Tier 1 — ML enhancement (NOT reachable)

Adobe Podcast Enhance Speech and Descript Studio Sound are one button that strips background noise, echo and room reverb, and rebuild the voice as if recorded in a studio. Adobe's v3 does source separation and exposes a strength slider. This is generative ML, not filtering — there is no arrangement of EQ, compression or gating that reaches it. Denoising and de-reverberation are the single most-requested thing in our own internal feedback, and we cannot do them with this effect set. Any catalog that quietly implies otherwise is lying.

Tier 2 — intent panels over conventional DSP (the model to copy)

Premiere Pro's Essential Sound panel is the closest analogue to what is being asked for, and it is the design worth stealing. The author tags a clip by what it is — Dialogue, Music, SFX, Ambience — and then gets a small set of outcome-named controls rather than effects:

• Loudness, with an Auto-Match that normalises to a broadcast target
• Repair — Reduce Noise, Reduce Rumble, DeHum, DeEss, Reduce Reverb, each a single intensity slider
• Clarity, which boosts the bands that make consonants distinct
• Creative, for reverb/space

Note the shape: one noun per problem, one slider per noun, no frequencies on screen. That is exactly what carve does with its strength knob, and it is the contract this catalog should hold to.

Tier 3 — character effects (fully reachable, and where consumer volume is)

CapCut ships ~100 voice filters and ~100 "voice characters". The named ones that recur across tools: Telephone, Megaphone, Radio/Radio Fuzz, Loudspeaker / PA Speaker, Intercom, Lo-Fi, Cassette Tape, Cave, Echo, Broadcast, Retro.

These are ordinary filter + saturation + bitcrush recipes and we can do all of them. The character half of CapCut's list we cannot do: Chipmunk, Deep Voice, Robot, Alien, Monster, Elf — every one of those is pitch, formant or ring modulation, and the registry has no pitch shifter, no time-stretch and no ring mod. Out of scope unless a new effect is added.

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3. What our 15 effects reach

Family	Effects	Reaches
Filter	highpass lowpass peaking lowshelf highshelf	tone shaping, band isolation, rumble/mud removal, presence
Dynamics	gain compressor limiter gate	levelling, consistency, ceilings, room-tone gating
Nonlinear	saturate bitcrush	warmth, grit, distortion, digital degradation
Time	delay reverb chorus phaser	space, slap, width, wow/flutter, movement

Plus two force multipliers the catalog depends on:

• Automation lanes on gain and on most effect parameters — so a preset can be a moving treatment, not just a static one.
• Offline analysis (powerSpectrum, windowDb, analyseCarveDynamics, analyseCarveDuck) already runs in the panel over decoded audio. This is what makes the adaptive tier possible without new machinery.

Hard limits, stated once: no noise reduction, no de-reverberation, no pitch or formant shift, no time-stretch, no spectral repair, no stereo widening beyond chorus, no true multiband compression (though stacked peaking + a mix-blended compressor approximates it).

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4. Two mechanisms, and carve is already the second

The user's instinct to say "presets/scripts" is the right split.

Static presets — a chain literal

Mirrors HF_COLOR_GRADING_PRESETS exactly: named, fixed parameter values, one click, fully editable afterwards. Suits anything whose right answer does not depend on the audio — every character effect, every space, and the corrective voice chains at a sensible default.

Adaptive scripts — measure, then generate

The carve pattern: read the decoded samples, measure something, emit a chain and/or automation lanes. The machinery for this is already built and shipped — what carve does with a voice against a bed generalises:

Script	Reuses	Emits
Voice carve (shipped)	analyseCarveBands	peaking cuts + per-band lanes
Auto-duck (shipped, inside carve)	analyseCarveDuck	one volume lane
De-esser	analyseCarveDynamics, re-parameterised (see §5e)	lane on a peaking cut
Leveller	windowDb walk	lane on a gain node
Tone match	powerSpectrum vs a target curve	3–5 peaking nodes

This is the strongest argument in the doc: none of them needs new DSP — only a different question asked of code that already runs. One (de-ess) needs that code re-parameterised for a shorter timescale; the rest reuse it as-is.

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5. Proposed catalog

Every value below is inside the registry's declared range. Node order is the canonical one the skill already states: gate → subtractive EQ → compressor → presence EQ → saturation → limiter last.

5a. Voice (static)

voice-clean — "Clean Voice" · the safe default, roughly Premiere's Dialogue preset

highpass   frequency 80    q 0.707  poles 2
peaking    frequency 250   gain -3   q 1.2      (mud)
compressor threshold -20  ratio 3  attack 12  release 180  makeup 3
peaking    frequency 3000  gain +2.5 q 1.0      (presence / consonants)
limiter    limit -1  attack 5  release 50

voice-broadcast — "Broadcast" · denser, more forward

highpass   frequency 90    q 0.707  poles 2
peaking    frequency 400   gain -3   q 1.4
compressor threshold -24  ratio 4  attack 8  release 150  makeup 5
peaking    frequency 2500  gain +3   q 0.9
highshelf  frequency 8000  gain +2                        (air)
saturate   type tanh  threshold -12  output 0             (glue)
limiter    limit -1  attack 5  release 60

voice-warm — "Close & Warm" · intimate, less processed

highpass   frequency 70    q 0.707  poles 2
lowshelf   frequency 180   gain +2
compressor threshold -18  ratio 2.5  attack 20  release 250  makeup 2
peaking    frequency 3000  gain +1.5 q 0.8
limiter    limit -1.5

Frequency choices are the documented conventions: high-pass at 60–80 Hz for voice, 150–300 Hz is where proximity-effect mud lives, and presence for consonant intelligibility sits around 2–4 kHz.

5b. Repair — honestly named (static)

These are the reachable half of Premiere's Repair section. The names must not promise noise removal.

rumble-cut — "Cut Rumble" — highpass 100 Hz, poles 2. Two stacked nodes for 24 dB/oct when a source is badly affected.

room-gate — "Quiet Between Phrases" — gate threshold −45, range −18, ratio 10, attack 2, release 180. This gates, it does not denoise: room tone still sits under speech, it is only silenced in the gaps. Label it that way in the UI or it will be mistaken for Tier 1.

boom-tame — "Tame Boominess" — peaking 200 Hz, −4 dB, Q 1.4.

harsh-tame — "Soften Harshness" — peaking 3.2 kHz, −3 dB, Q 1.6. Static and broad on purpose; sibilance proper is a script (§5e), not a fixed cut.

5c. Character (static)

telephone — "Telephone" · the researched 300–3400 Hz band, steepened

highpass   frequency 300   q 0.707  poles 2   ×2 stacked  (24 dB/oct)
lowpass    frequency 3400  q 0.707  poles 2   ×2 stacked
peaking    frequency 1200  gain +6  q 1.2                 (the "honk")
peaking    frequency 550   gain -4  q 1.0                 (de-mud)
saturate   type tanh  threshold -18  output -2            (circuit colour)

The registry maxes at 12 dB/oct per node (poles: "2"), so the classic 24 dB/oct skirts need two stacked nodes each. Worth encoding once here rather than having every author rediscover it.

radio-am — "AM Radio" — band 400–3000 Hz, saturate tanh threshold −15 output −2, bitcrush bits 10 samples 1 mix 0.25.

megaphone — "Megaphone" — highpass 500, lowpass 4000, peaking 1800 +8 Q 1.5, saturate hard threshold −12 output −3, delay time 40 ms feedback 0.15 mix 0.15 (the horn's slap).

lofi-tape — "Tape" — lowpass 6500, lowshelf 120 +2, bitcrush bits 12 samples 2 mix 0.35, saturate tanh threshold −14, and chorus delay 6, depth 0.6, speed 0.4, mix 0.15 — a slow shallow chorus is exactly how you fake wow and flutter, which is a genuinely nice use of an effect we have.

pa-system — "Tannoy / PA" — band 350–3500, peaking 1500 +5 Q 1.2, saturate tanh threshold −16, reverb size 0.5 damping 0.7 wet 0.25 dry 0.8.

intercom — "Intercom" — band 500–3000, peaking 2000 +6 Q 2, bitcrush bits 11 mix 0.3, gate threshold −40 range −30 (the squelch).

5d. Space (static)

room-tight — reverb size 0.25, damping 0.6, wet 0.18, dry 0.9 room-natural — size 0.5, damping 0.5, wet 0.25, dry 0.85 hall — size 0.9, damping 0.3, wet 0.4, dry 0.75 slap-echo — delay time 110 ms, feedback 0.12, mix 0.22 dub-throw — delay time 375 ms, feedback 0.55, mix 0.3

5e. Adaptive scripts

de-ess — "Soften Sibilance" — must be a script, not a preset. A fixed −6 dB at 7 kHz dulls the whole voice; a de-esser only acts when sibilance is present. Run the carve pattern against the track's own 5–8 kHz band and emit a peaking node at the measured centre with a lane on its gain that dips only during sibilant windows. Sibilance centres around 5–6 kHz for lower voices, 7–8 kHz for higher — measure it rather than assuming.

analyseCarveDynamics cannot be reused unchanged here, and this is the one place in §5e that needs work rather than a new caller. Its hop is max(FRAME, length / POINT_BUDGET) — 85 ms at best and ~150 ms on a real-length track — while sibilants are 50–150 ms events, so at that resolution the envelope cannot land on them. Its ATTACK_S/RELEASE_S ballistics are tuned for musical ducking and are far too slow as well. Same machinery, same FFT, but it needs a sibilance-scale hop and much faster attack/release.

level-out — "Even Out Levels" — walk windowDb, emit a lane that lifts quiet passages and holds loud ones, against a target range rather than a fixed gain.

The lane must ride a gain node, not the volume lane. VOLUME_RANGE is 0..1 and normaliseEnvelope clamps every keyframe into it, so a volume lane can only ever attenuate — it cannot lift anything. A gain node spans −60..+12 dB and is automatable, which is exactly what the audio skill means when it calls gain "what an automation lane rides when a track has to move". So this script emits both a chain (one gain node) and the lane addressing it. Do not call this LUFS. windowDb is plain RMS; platform targets (−14 LUFS for Spotify/YouTube/TikTok/Instagram, −16 for Apple Music/podcasts) are ITU-R BS.1770 K-weighted and gated. Either implement the K-weighting prefilter — two biquads, entirely feasible offline with the filters we have — or name the feature "even out" and cite the targets as context only.

tone-match — "Match Tone" — powerSpectrum of the track against a target curve (a built-in "broadcast voice" curve, or another clip in the project), emitting 3–5 corrective peaking nodes. This is iZotope's Tonal Balance idea at a tenth of the complexity, and powerSpectrum already returns exactly the data it needs.

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5f. Module identity in the rack

The rack is a 292 px column of stacked modules — which is, near enough, a Eurorack case. Worth leaning into: a faceplate recognised by colour and lettering before the label is read. Carve already gets a distinct treatment (hf-fx-carve-module); this generalises it.

Direction chosen 2026-08-09: schematic — picked from four mocked alternatives (hardware silkscreen, vintage test equipment, risograph, schematic). Recorded with its principles in .impeccable.md at the repo root.

The rack is drawn as the signal path it is: numbered nodes on a dashed spine running from an IN terminal to an OUT, leader-dotted dimension lines, three-letter stage tags, family colour restricted to the node ring and the tag.

Why it won over the louder options: it is the only one that adds information. Chain order is load-bearing — a limiter first and a limiter last are different sounds — and nothing in the panel communicated it. It is also the quietest, which matters on a surface authors stare at while mixing.

What the drawing carries that the current rack cannot say:

Drawn as	Instead of
IN names the source, OUT names the destination and the FX tail	nothing — the tail was invisible
Numbered nodes 01…06	implicit top-to-bottom order
Bypassed node: ring drawn open, wire beside it solid and unbroken	a row at 50% opacity
Preset nodes gathered under a right-hand brace with its name	no grouping at all
An automated parameter's value reads live at the playhead and ticks while the transport runs, marked ~	the stale seed the lane already replaced
A measuring module gets a second ring	nothing distinguishes carve from a hand-set chain

That last pair is the static-versus-script distinction from §4, delivered as drawing rather than documentation.

Automated parameters show numbers, not shapes. An earlier pass drew each lane's envelope inside the module; that was dropped. The lane already has a home in the timeline, and a second small drawing of it in the rack is decoration — what the rack is missing is the current value. The panel already receives it: FxSectionProps.liveAutomationValues exists precisely because "an automated parameter's stored number is only the seed the lane replaced, so a rack that shows it stands still while the carve is audibly working". So the row is an ordinary parameter row whose number is live, ~ on the label saying it is driven rather than set, and the marker moving with it. Stopped, the values go grey and hold at the playhead.

The preset menu preview is the chain — each row previews the nodes it will draw as small connected rings in their family colours, so the shape you pick is the shape you get. Smart entries read MEASURES instead.

The empty state keeps the wire. IN and OUT remain, connected, with "no effects, signal passes straight through" between them — which teaches that the rack is a path before the author has added anything to it.

Not carried over from the first pass: the 3 px coloured rail down each module's left edge. It is the most overused device in dashboard UI, and forcing each direction to find another answer is what separated them.

Family hues, chosen to sit on #0C0C0E without competing with the studio's #3CE6AC accent:

Family	Hue	Why
Filter	#4FA8FF	the measuring family
Dynamics	#FFB443	grips the signal
Nonlinear	#FF6B5C	the only generative family
Time	#B98CFF	atmosphere, not control
Smart	#3CE6AC	the studio's own accent — reserved for modules that act on their own

This needs almost no new plumbing. group is already on every effect in the registry, so hue and lettering are derived, not hand-assigned. And every module already renders data-fx-node="<type>", so the whole identity layer is CSS on an attribute that exists today. Only "Smart" is new, and carve already lives there in spirit.

Type budget is the real decision. Fonts must be self-hosted (no CDN). Recommended: two faces — the UI sans plus one characterful display face split across families. One face is too subtle at 11 px; five is a bundle cost and starts reading as a collage on a surface authors stare at while mixing.

Preset menu: grouped by the same families, so the colour picked in the menu is the colour that appears in the rack. Each row carries the number of modules it drops in — which quietly teaches that a preset is a chain. Smart entries say "measures" instead of a count, which is the entire static-vs-adaptive distinction delivered in one word.

Open decisions: whether applying a preset appends or replaces (suggest append, replace on modifier, re-apply swapping its own fromPreset nodes); the type budget above; and whether character presets get drawn glyphs on their plates — the biggest step toward "fun", and the only part needing artwork rather than CSS.

Mockup at the real panel width: published as an artifact, 2026-08-09.

6. Architecture

Mirror colour grading, because the author already understands that surface.

export interface HfAudioFxPreset {
  id: string; // "telephone"
  label: string; // "Telephone"
  family: "voice" | "repair" | "character" | "space";
  description: string; // one line, in the author's language
  chain: HfAudioFxChain; // an ordinary chain — nothing special
  automation?: HfAutomation; // for presets that move
}

Four notes:

1. A preset is just a chain. Applying one writes data-fx-chain exactly as hand-building would. It is inspectable, editable and undoable, and it cannot introduce a failure mode the rack does not already have.
2. Tag the nodes. HfAudioFxNode already carries fromCarve; an analogous fromPreset: "telephone" lets the panel show "Telephone (edited)" and lets a re-apply replace its own nodes without touching hand-added ones.
3. Fixed values in v1, no intensity knob. Colour grading's presets are fixed; carve earned its strength knob by being adaptive. Most effects carry a mix parameter, which is the natural hook if intensity is wanted later — note it, don't build it.
4. Scripts need a separate registry with an analyse(samples, sampleRate) → { chain, automation } contract, because they cannot be static data. Carve is the reference implementation.

Two things that will otherwise be filed as bugs

• Boost presets must end in a limiter. voice-broadcast adds presence and +5 dB makeup; without its limiter it will overshoot full scale. The clip-before-duck fix (55f852a72) makes that survivable, but the measured damage still scales with overshoot — 2.7× peak destroys 19% of samples. A preset that ships hot is a bad preset regardless of what the render does about it.
• Worklet-backed presets play dry for a moment in preview. Anything containing compressor, limiter, gate or bitcrush waits for ensureAudioFxWorklets before it can be built — so nearly every voice preset is momentarily dry on first apply, then swaps in. Expected, not a defect.

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7. What to build first

1. Character presets (§5c) — highest ratio of delight to risk. Pure filter/saturation data, instantly recognisable, nothing to measure, and the category consumer tools get the most use out of.
2. Voice presets (§5a/b) — the practical value, and the answer to the internal asks already in cortex.
3. level-out — the most-wanted adaptive one, and the smallest script.
4. de-ess, then tone-match — both reuse carve's analysis directly.

Deliberately not proposed: anything requiring a new effect. If pitch shifting ever lands, the whole character half of CapCut's list opens up at once — but that is a new DSP conversation, and this doc is explicitly the one that does not need one.

If this ships

CLAUDE.md's skill-catalog rules apply: a preset catalog changes what /hyperframes-audio covers, so the skill's description: and the surfaces listed under "Skill catalog maintenance" have to move in lockstep.

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Sources

Internal: wiki/decisions/vst-studio-integration-cancelled.md; skills/hyperframes-audio/SKILL.md; packages/core/src/audioFx.ts (ranges); packages/core/src/audioCarve.ts (the script pattern); packages/core/src/colorGrading.ts (the preset pattern). Cortex: studio acoustics reprocessing, voice loudness and gain boosting.

External:

• Adobe Podcast Enhance Speech guide and Adobe vs Descript shootout — Tier 1 boundary
• Premiere Pro Essential Sound panel guide and Envato's dialogue walkthrough — the intent-panel model
• Rode's podcast processing guide, Podigy on podcast EQ and iZotope on de-essing — voice chain values and sibilance ranges
• CapCut voice filters and its full effect list — Tier 3 vocabulary
• Telephone effect settings and Audiotent's walkthrough — the 300–3400 Hz band and its refinements
• LUFS targets per platform 2026 and podcast loudness standards — why level-out must not claim LUFS