# TODO-1.0 Post-1.0 enhancement queue for the ReaSampler 9000 instrument. Three items, in Daniel's ordering (2026-07-28). Deliberately specified at the level of product intent, user-visible behavior, and acceptance criteria — **no implementation design, no file/module references**. These were authored while Phase Q was restructuring the tree; the implementing engineer maps each spec onto the post-Q layout at execution time. Each item preserves Daniel's raw ask verbatim as the source of truth, then breaks it into behavior, open questions, and an observable acceptance gate. Ordering note: item 1's curve/overlay treatment explicitly anticipates item 2's filter envelope ("filter to be added"), and item 3 layers on both. They can land in sequence or together, but 1 and 2 are prerequisites for 3's full surface. --- ## 1 — Envelope editor: per-deck radio switch, segment curve dials, overlay recolor **Daniel's ask (verbatim, 2026-07-28).** > The VST envelope editor visual is a great start but we need to add some > features. The Amp AHDSR is currently always displayed. We need to add a radio > switch to the corner of each env knob deck which makes THAT envelope editable > via the graphic waveform overlay. This is currently the amp and pitch > envelopes, with filter to be added (see below). All envelopes (amp AHDSR, > Pitch AD, Filter AHDSR) should be enhanced to have editable segment curve > values. This should be an exponential function with the exponent scalar > parameter for each sloped segment having possible values from 0.1 to 10. The > knob deck radial knobs for the sloped curvable segments will have an INNER > dial, with its own inner arc, hover accent (tertiary purple), needle, and > numerical label which controls the curve for that sloped segment. Also the > graphical envelope editor draws its segments in secondary blue, which > contrasts poorly against the primary green waveform display. Change those to > tertiary purple. **Intent.** Grow the envelope-overlay editor from an amp-only fixture into the shared graphical surface for every envelope in the instrument, and give every envelope shapeable (non-linear) segments — while fixing the blue-on-green contrast failure. **Behavior.** - **Radio switch per envelope deck.** Each envelope knob-deck group (currently AMP ENVELOPE and PITCH ENV; the filter envelope joins when item 2 lands) gains a radio switch in the corner of its deck. Selecting a deck's radio makes *that* envelope the one displayed and editable in the graphic waveform overlay — replacing today's behavior where the Amp AHDSR is always the displayed envelope. - **Segment curve values on all envelopes.** Amp AHDSR, Pitch AD, and Filter AHDSR all gain an editable curve value per *sloped* segment. The curve is an exponential function; the per-segment parameter is the exponent scalar, range **0.1 to 10**. - **Inner dial on curvable-segment knobs.** Every knob-deck radial knob that controls a sloped, curvable segment gains an **inner dial**: its own inner arc, its own hover accent (tertiary purple), its own needle, and its own numerical label. The inner dial controls the curve exponent for that segment; the outer knob keeps controlling the segment's time/level value as today. - **Overlay recolor.** The graphical envelope editor's segments change from secondary blue to **tertiary purple** (secondary blue contrasts poorly against the primary green waveform behind it). **Open questions.** - **Radio exclusivity + default.** "Radio" implies exactly one envelope is overlay-active at a time across all decks — confirm that reading, and confirm the Amp AHDSR remains the default selection on open. - **Which segments are "sloped."** Per envelope type, which segments carry a curve dial? (E.g. Attack/Decay/Release obviously slope; Hold and Sustain presumably do not — needs Daniel's confirmation per stage.) - **Curve default and neutral point.** Is exponent 1.0 the linear/neutral default, and should existing saved instances load with all curves at the linear-equivalent so their sound is unchanged? (Persistence extension is implied; the product requirement is only "old instances sound identical.") - **Curve editing in the overlay.** Is the curve exponent editable *from the overlay itself* (e.g. dragging a segment's belly), or is the inner dial the sole curve-edit affordance and the overlay edits node positions only? Daniel's ask specifies the dial; overlay curve-drag is not stated either way. **Acceptance criteria.** - Each envelope deck shows a corner radio switch; activating one puts that envelope in the overlay, editable there, and the overlay tracks the switch immediately. - Every curvable-segment knob shows the inner dial (inner arc, tertiary-purple hover accent, needle, numeric label); sweeping it through 0.1 → 10 visibly reshapes the overlay segment and audibly reshapes the envelope on played notes. - Overlay envelope segments render in tertiary purple and are clearly legible against the primary green waveform. - A project saved before this change reopens with unchanged audible envelope behavior. --- ## 2 — MM preamp Filter: resonant HP/LP stage in the voice pipeline **Daniel's ask (verbatim, 2026-07-28).** > MM preamp Filter: We must implement a new processing point in the sampler > audio pipeline, after pitch env, before amp, for filtering. The processor for > this will be based on code I wrote for the cortex M4 for resonant high and > lowpass filtering. The filter will have parameters for mode, cutoff, Q, and > mod amt, then the AHDSR controls as described above. The knob deck row will > then be relaid out in signal flow order: pitch -> filter -> amp **Intent.** Add the instrument's first filter stage — resonant high-pass and low-pass — as a new fixed point in the per-voice signal path, with its own AHDSR envelope, and make the knob-deck row read in signal-flow order. **Behavior.** - **Pipeline position.** A new processing point in the sampler audio pipeline: **after the pitch envelope, before the amp stage.** - **DSP source.** The filter processor is based on Daniel's own Cortex-M4 resonant high/lowpass filter code. **That code is an input Daniel supplies at implementation time** — it is not in this repo and this spec does not characterize it beyond "resonant high and lowpass." - **Parameters.** Mode, cutoff, Q, and mod amt — then the AHDSR controls, treated exactly as item 1 specifies (curvable sloped segments with inner dials, overlay editability via the filter deck's radio switch). - **Deck reorder.** The knob deck row is relaid out in signal-flow order: **pitch → filter → amp**. **Open questions.** - **Mode list.** Is mode a discrete selector, and over exactly which entries? "Resonant high and lowpass" confirms HP and LP; whether band-pass/notch or multiple slopes exist depends on the Cortex-M4 source and Daniel's intent. - **Ranges and units.** Cutoff range (Hz), Q range, and mod-amt range/polarity (unipolar or bipolar?) are unstated — likely settled by the Cortex-M4 code plus a Daniel call at implementation time. - **Mod routing.** "Mod amt" presumably scales the filter AHDSR's modulation of cutoff — confirm the target is cutoff and whether any other mod sources (velocity, key-tracking) are in scope now or deferred. - **Scope: per-zone or per-instance.** Existing playback parameters live per-zone with Sample/Zone panel parity; VOICE and MASTER are per-instance exceptions. Which side does the filter fall on? - **Neutral default.** Should the filter default to a bypass/neutral state so pre-existing saved instances (and freshly loaded captures) sound unchanged until the user engages it? - **Display name.** Is "MM Preamp Filter" the user-facing label for the deck group, or working shorthand? **Acceptance criteria.** - With the filter engaged, played notes are audibly filtered at the specified pipeline point: the filter acts on pitched (post-pitch-envelope) signal, and the amp envelope still shapes the filtered result (audible ordering: pitch → filter → amp). - Mode, cutoff, Q, and mod-amt controls appear in a filter deck group; the filter AHDSR gets the full item-1 treatment (curve inner dials, corner radio switch, tertiary-purple overlay editing). - High Q audibly emphasizes the cutoff region (resonance) in both HP and LP modes. - The deck row reads pitch → filter → amp left-to-right. - A project saved before this change reopens sounding identical (pending the neutral-default confirmation above). --- ## 3 — Alternative Spline EGs: hard/smooth multi-segment monotonic splines **Daniel's ask (verbatim, 2026-07-28).** > Alternative Spline EGs: Every processor which has an envelope will have the > ability to change the Staged EG to a Spline EG, based on the monotonic > splines for the velocity curve. HOWEVER, we will need to enhance the (singly > implemented, multi referenced) spline algorithm to support multiple segments > that DON'T minimally smooth the spline, so that hard points are possible. In > other words, the contour of the EG will be defined by 1 or more monotonic > spline functions which together form the full time function for that > processor, such that the first three points could make a curved segment, > which connects at a sharp angle to the next three points, finishing out the > contour over the full sample length. Control-clicking a point makes it a > "hard" or "smooth" point (toggled, smooth by default) which when hard does no > curve smoothing on either side segment, forming the natural sharp angle > instead of a continuous derivative. This enhanced spline drawing will be used > for the velocity-amp transfer curve as well as the pitch, filter, and amp EGs > (if they are in spline mode). **Intent.** Offer a free-drawn alternative to every staged envelope: the user switches any EG from Staged to Spline mode and draws the contour directly, with the monotonic-spline machinery already proven by the velocity curve — enhanced so sharp corners are possible, not everything smoothed. **Behavior.** - **Mode toggle per EG.** Every processor that has an envelope (pitch, filter, amp) can switch its Staged EG to a **Spline EG**. - **Spline foundation.** The Spline EG is based on the monotonic splines used for the velocity curve. The spline algorithm is singly implemented and multi-referenced; the enhancement below applies to that one implementation and flows to every consumer. - **Hard points.** The algorithm is enhanced to support **multiple segments that don't minimally smooth the spline**, so hard points are possible: the EG contour is defined by **one or more monotonic spline functions** which together form the full time function for that processor — e.g. the first three points form a curved segment that connects **at a sharp angle** to the next three points, finishing the contour over the **full sample length**. - **Hard/smooth gesture.** **Control-clicking a point toggles it hard/smooth (smooth by default).** A hard point does no curve smoothing on either adjacent segment — the natural sharp angle stands instead of a continuous derivative. - **Shared across consumers.** The enhanced spline drawing serves the **velocity→amp transfer curve** as well as the pitch, filter, and amp EGs (when those are in spline mode). The velocity curve gains hard-point support by the same enhancement. **Open questions.** - **Staged↔Spline toggle semantics.** What happens to a Staged EG's values when toggling to Spline mode and back? (Convert the staged shape into an initial spline? Keep two independent per-mode states? Discard?) Daniel has not said — this materially shapes both UX and persistence and needs his call. - **Gate-mode sustain/release.** A Staged Gate envelope holds at Sustain and releases on note-off; a spline contour drawn "over the full sample length" is a pure time function. How do note-off, sustain, and looped playback map onto a Spline EG in Gate mode? (Trigger/one-shot is the natural fit; Gate needs a stated rule.) - **Time axis.** Is the contour's time axis normalized to the sample length (so it rescales with the sample) or absolute seconds? "Over the full sample length" suggests sample-relative — confirm, especially for looped sustain. - **Monotonicity meaning.** The velocity spline is monotone to prevent overshoot on a transfer curve. An EG contour must rise and fall; presumably "monotonic" here means the per-segment no-overshoot property (values never exceed the segment's endpoints), not a globally monotone function — confirm the intended guarantee. - **Point-editing grammar.** Point add/delete gestures and any point-count bound are unstated. The velocity-curve popup already established right-click node delete — reuse of that grammar seems natural but is Daniel's call. - **Interaction with item-1 curve dials.** In Spline mode, do the staged segment knobs/inner dials go inert (shape comes wholly from the spline), or is some hybrid intended? Presumably the former — confirm. **Acceptance criteria.** - Each of the pitch, filter, and amp EGs offers a Staged/Spline mode switch; in Spline mode the overlay (via the item-1 radio switch) shows and edits the drawn contour, and played notes audibly follow it. - Control-click toggles any point hard/smooth; points are smooth by default; a hard point renders a visible sharp angle with no smoothing on either adjacent segment, and the discontinuous slope is audible where the modulation target makes it so (e.g. a pitch EG corner). - A contour of several segments joined at hard points plays back over the full sample length exactly as drawn. - The velocity→amp transfer-curve editor supports the same control-click hard/smooth toggle with identical rendering behavior. - Staged↔Spline toggling behaves per the answered open question above (that answer gates this item's completion definition).