tables.hpp

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#pragma once
 
// Calibration tables for the multi-character delay.
//
// This file is the module's tuning surface. Every value that was CHOSEN rather
// than derived sits here as a named constant on a knot table, so retuning the
// module by ear — or replacing a table wholesale with values measured from a
// real machine — is a data edit that touches no DSP logic. Nothing in this
// file is transcribed from another framework's source or from unpublished
// measurements; the mechanisms are from the open literature (see the module
// header for the concept-to-citation map) and the numbers are our own starting
// points.
//
// Values that are NOT design parameters — published physical or mathematical
// constants — are marked as such inline and are not knot tables: they are facts
// (chip stage counts, the 50 µs emphasis time constant, Butterworth pole Qs,
// γ-Fe2O3 material constants, Dattorro's published diffuser network) and moving
// them would make the model wrong rather than differently tuned.
 
#include <pulp/signal/oversampling_fir.hpp>
 
#include <array>
#include <cstddef>
#include <cstdint>
 
namespace pulp::signal::chardelay {
 
// ── Engine-wide ───────────────────────────────────────────────────────────

inline constexpr double kMaxDelayMs = 2000.0;
inline constexpr double kTimeOffsetMin = 0.5;
inline constexpr double kTimeOffsetMax = 1.5;
inline constexpr double kMaxAddressableDelayMs = kMaxDelayMs * kTimeOffsetMax;

inline constexpr int kControlInterval = 32;

inline constexpr double kParamGlideS = 0.005;

inline constexpr double kUnsaturatedFeedbackMax = 0.98;

inline constexpr double kSaturatedFeedbackMax = 1.1;

inline constexpr double kModRateMinHz = 0.05;
inline constexpr double kModRateMaxHz = 10.0;
inline constexpr double kModMaxDepth = 0.05;

inline constexpr double kLoopToneHpMinHz = 20.0;
inline constexpr double kLoopToneHpMaxHz = 2000.0;
inline constexpr double kLoopToneLpMinHz = 200.0;
inline constexpr double kLoopToneLpMaxHz = 20000.0;
inline constexpr double kLoopToneNyquistFraction = 0.45;
inline constexpr double kLoopToneResMin = 0.5;
inline constexpr double kLoopToneResMax = 2.0;

inline constexpr double kStereoDecorr = 0.95;

inline constexpr std::uint32_t kPrngSeed = 74207u;
 
// ── Delay-time slew, per character ────────────────────────────────────────
// The character's transport inertia, in milliseconds. Every character reads
// through a slewed continuous time, so a time change produces the physically
// correct pitch glide; there is deliberately no crossfade-jump path anywhere.
// [all design parameters]
inline constexpr double kTimeSlewCleanMs = 15.0;      // 5–30, de-zipper only
inline constexpr double kTimeSlewVintageMs = 50.0;    // 30–80, clock glide
inline constexpr double kTimeSlewTapeMs = 250.0;      // 150–400, motor/capstan lag
inline constexpr double kTimeSlewBbdMs = 80.0;        // 50–150, clock glide
inline constexpr double kTimeSlewDiffusionMs = 15.0;  // 5–30, de-zipper only
 
// ── Clean Modern ──────────────────────────────────────────────────────────
// [all design parameters]
inline constexpr std::array<double, 3> kCleanAxis = {0.0, 0.5, 1.0};
inline constexpr std::array<double, 3> kCleanLoopLpHz = {20000.0, 12000.0, 6000.0};
inline constexpr std::array<double, 3> kCleanLoopHpHz = {20.0, 20.0, 120.0};

inline constexpr double kLoopLpBypassHz = 20000.0;
 
// ── Vintage Digital ───────────────────────────────────────────────────────
// No open paper documents the early-80s rack units this character evokes; the
// MECHANISMS are the published general ones (band-limited clocked conversion,
// pre/de-emphasis around a quantizer, low-bit PCM artifacts — Välimäki et al.
// 2008), but every value below is a design parameter.
inline constexpr std::array<double, 4> kVintageAxis = {0.0, 0.33, 0.67, 1.0};
inline constexpr std::array<double, 4> kVintageInternalRateHz = {32000.0, 24000.0, 16000.0,
                                                                 8000.0};
inline constexpr std::array<double, 4> kVintageBits = {14.0, 12.0, 12.0, 10.0};

inline constexpr double kVintageAntiAliasFraction = 0.45;

inline constexpr double kVintageEmphasisHz = 3183.0;
inline constexpr double kVintageEmphasisDb = 9.0;
 
// ── Tape (standard tier) ──────────────────────────────────────────────────
// [all design parameters unless noted]
inline constexpr std::array<double, 4> kTapeAxis = {0.0, 0.33, 0.67, 1.0};
inline constexpr std::array<double, 4> kTapeDrive = {1.5, 2.5, 4.0, 6.0};
inline constexpr std::array<double, 4> kTapeBias = {0.0, 0.10, 0.20, 0.30};
inline constexpr std::array<double, 4> kTapeWowDepthMs = {0.0, 0.15, 0.5, 1.2};
inline constexpr std::array<double, 4> kTapeFlutterDepthMs = {0.0, 0.05, 0.15, 0.4};
inline constexpr std::array<double, 4> kTapeLossLpHz = {12000.0, 9000.0, 6000.0, 3500.0};
inline constexpr std::array<double, 4> kTapeBumpDb = {1.5, 2.0, 3.0, 4.0};

inline constexpr std::array<double, 4> kTapePhysicalFeedbackCompensation = {
    0.3739533963, 0.3530347705, 0.3146425708, 0.2804254864};

inline constexpr double kTapeEmphasisDb = 3.0;    // 0–6
inline constexpr double kTapeEmphasisHz = 1600.0; // 1–3 kHz

inline constexpr double kTapeBumpHz = 60.0;
inline constexpr double kTapeBumpQ = 1.5;

inline constexpr double kTapeDcBlockHz = 15.0;

inline constexpr double kWowRateHz = 1.0;
inline constexpr double kWowOuTheta = 1.5;      // s^-1 mean-reversion
inline constexpr double kWowOuSigma = 0.6;      // innovation scale
inline constexpr double kWowOuNoiseLpHz = 10.0; // pre-filter on the innovation

inline constexpr double kFlutterBaseHz = 8.0;
inline constexpr std::array<double, 3> kFlutterAmplitudes = {1.0, 0.5, 0.25};
inline constexpr std::array<double, 3> kFlutterPhases = {0.0, 0.33, 0.71};  // cycles

inline constexpr double kFlutterPhaseRight = 0.41;
 
// ── BBD ───────────────────────────────────────────────────────────────────
inline constexpr std::array<double, 3> kBbdAxis = {0.0, 0.5, 1.0};

inline constexpr std::array<double, 3> kBbdStages = {4096.0, 2048.0, 1024.0};
 
inline constexpr std::array<double, 3> kBbdDrive = {0.10, 0.30, 0.50};
inline constexpr std::array<double, 3> kBbdJitterAmount = {0.0, 0.3, 0.6};
inline constexpr std::array<double, 3> kBbdFlutterDepth = {0.0, 0.005, 0.015};

inline constexpr std::size_t kBbdMaxStages = 4096;

inline constexpr int kBbdOversample = 16;

inline constexpr double kBbdBandwidthDivisor = 3.0;
inline constexpr double kBbdBandwidthMinHz = 300.0;
inline constexpr double kBbdBandwidthMaxHz = 10000.0;
inline constexpr double kBbdFilterCutoffScale = 2.1;

inline constexpr double kBbdCompanderTauMs = 10.0;
inline constexpr double kBbdCompanderFloor = 0.01;

inline constexpr double kBbdCompanderDriveScale = 0.3;

inline constexpr double kBbdDriveGainSpan = 9.0;  // drive 0..1 → gain 1..10
inline constexpr double kBbdShape = 0.25;         // 0–0.5

inline constexpr double kBbdJitterMax = 5e-4;
inline constexpr double kBbdJitterSmoothness = 0.5;

inline constexpr double kBbdFlutterRateBaseHz = 0.3;
inline constexpr double kBbdFlutterRateSpanHz = 1.2;
 
// ── Diffusion ─────────────────────────────────────────────────────────────
// The base network is Dattorro's PUBLISHED input diffuser (Effect Design Part
// 1, Table 1): 142/107/379/277 samples at his 29.8 kHz reference rate, given
// here in milliseconds, with his published coefficients. Only the scalings are
// design parameters.
inline constexpr std::array<double, 4> kDiffusionStageMs = {4.7651, 3.5906, 12.7181,
                                                            9.2953};
inline constexpr std::array<double, 4> kDiffusionStageGain = {0.75, 0.75, 0.625, 0.625};
 
inline constexpr std::array<double, 3> kDiffusionAxis = {0.0, 0.5, 1.0};
inline constexpr std::array<double, 3> kDiffusionSizeScale = {0.5, 1.0, 1.7};
inline constexpr std::array<double, 3> kDiffusionGainScale = {0.7, 1.0, 1.12};

inline constexpr double kDiffusionGainMax = 0.85;

inline constexpr double kDiffusionModDepthSamples = 2.0;
inline constexpr std::array<double, 2> kDiffusionModRatesHz = {0.40, 0.53};

inline constexpr double kDiffusionLoopHpHz = 20.0;
inline constexpr double kDiffusionLoopLpHz = 9000.0;
 
// ── Diffusion tank ────────────────────────────────────────────────────────
// The input diffuser above smears a transient, but on its own it cannot make a
// reverb: it has no recirculation of its own, so between the delay's repeats
// there is silence and the character reads as a smeared slap rather than a
// cloud. The tank is Dattorro's figure-of-eight (Effect Design Part 1, Fig. 2)
// — two branches, each an allpass, a delay, a damping lowpass, a second
// allpass and a second delay, cross-coupled through a decay coefficient — so
// energy circulates on its OWN short time constants and fills the gaps.
//
// It blooms with character_amount and is exactly ZERO at amount 0, which keeps
// the pure-diffuser configuration a magnitude-flat allpass (the null-test
// baseline the character is specified against).
inline constexpr std::array<double, 3> kDiffusionTankAxis = {0.0, 0.5, 1.0};

inline constexpr std::array<double, 2> kDiffusionTankDelayAMs = {30.51, 44.79};
inline constexpr std::array<double, 2> kDiffusionTankDelayBMs = {37.13, 53.27};
inline constexpr std::array<double, 2> kDiffusionTankApAMs = {22.58, 60.48};
inline constexpr std::array<double, 2> kDiffusionTankApBMs = {30.24, 89.24};
inline constexpr double kDiffusionTankApGain1 = 0.70;
inline constexpr double kDiffusionTankApGain2 = 0.50;

inline constexpr std::array<double, 3> kDiffusionTankSizeScale = {0.6, 1.0, 1.6};
inline constexpr std::array<double, 3> kDiffusionTankDecay = {0.0, 0.62, 0.80};

inline constexpr std::array<double, 3> kDiffusionTankMix = {0.0, 0.55, 0.85};

inline constexpr std::array<double, 3> kDiffusionTankDampHz = {12000.0, 7000.0, 4200.0};

inline constexpr std::array<double, 3> kDiffusionTankModDepth = {0.0, 14.0, 42.0};
inline constexpr std::array<double, 2> kDiffusionTankModRatesHz = {0.83, 1.27};
inline constexpr std::array<double, 2> kDiffusionTankTapFraction = {0.37, 0.71};

inline constexpr double kDiffusionTankLowGuardHz = 90.0;
inline constexpr double kDiffusionTankDelaySlewMs = 5.0;
 
// ── Reverse ───────────────────────────────────────────────────────────────
inline constexpr int kReverseFadeSamples = 96;

inline constexpr double kReverseLineMs = 30.0;
 
// ── Ducking ───────────────────────────────────────────────────────────────
// [all design parameters]
inline constexpr double kDuckAttackS = 0.005;   // 1–20 ms
inline constexpr double kDuckReleaseS = 0.250;  // 50–1000 ms
inline constexpr double kDuckThreshold = 0.1;   // ≈ −20 dBFS
 
// ── Physical tape tier ────────────────────────────────────────────────────

inline constexpr double kJaSaturationMagnetization = 3.5e5;  // M_s
inline constexpr double kJaAnhystereticShape = 2.2e4;        // a
inline constexpr double kJaPinning = 2.7e4;                  // k
inline constexpr double kJaReversibility = 0.2;              // c, published 0.1–0.3
inline constexpr double kJaInterdomainCoupling = 1.6e-3;     // α

inline constexpr int kJaMaxIterations = 8;
inline constexpr double kJaConvergenceThreshold = 6e-8;

inline constexpr double kJaLangevinClamp = 30.0;
inline constexpr double kJaSilenceThreshold = 1e-7;

inline constexpr std::size_t kHysteresisHalfBandTaps = kHouseHalfBandTaps;
inline constexpr double kHysteresisHalfBandStopbandDb = kHouseHalfBandStopbandDb;

inline constexpr double kJaMakeupToleranceDb = 1.0;

inline constexpr std::size_t kLossFirOrder48k = 96;
inline constexpr int kLossIirFitPoints = 64;

inline constexpr std::size_t kSpacingPoleSections = 3;
inline constexpr std::size_t kSpacingShelfSections = 8;
inline constexpr std::size_t kThicknessPoleSections = 1;
inline constexpr std::size_t kThicknessShelfSections = 2;
 
inline constexpr std::size_t kLossPoleSections =
    kSpacingPoleSections + kThicknessPoleSections;
inline constexpr std::size_t kLossShelfSections =
    kSpacingShelfSections + kThicknessShelfSections;

inline constexpr std::size_t kLossSearchDimension =
    kSpacingPoleSections + 2u * kSpacingShelfSections;

inline constexpr std::array<double, kSpacingPoleSections> kSpacingShapePoleX = {
    0.1736328177, 0.5872051207, 0.7066518389};
inline constexpr std::array<double, kSpacingShelfSections> kSpacingShapeShelfX = {
    0.0379101878, 0.8617586156, 1.195357912,  0.546821599,
    1.874319242,  1.250559327,  1.349688739,  0.5618309026};
inline constexpr std::array<double, kSpacingShelfSections> kSpacingShapeShelfDb = {
    -4.870968905, -22.02414799, -32.23365298, -35.9700058,
    -20.85639305, -35.24359399, -23.08806288, -40.0};
inline constexpr std::array<double, kThicknessPoleSections> kThicknessShapePoleX = {
    0.2127135512};
inline constexpr std::array<double, kThicknessShelfSections> kThicknessShapeShelfX = {
    0.03067430198, 0.1724152232};
inline constexpr std::array<double, kThicknessShelfSections> kThicknessShapeShelfDb = {
    -1.705785229, -0.6809460063};

inline constexpr double kLossShapeMinX = 1e-3;
inline constexpr double kLossShapeMaxX = 4.0;

inline constexpr int kLossIirFitIterations = 4000;
inline constexpr int kLossIirFitRestarts = 3;
inline constexpr int kLossIirFitStarts = 16;

inline constexpr double kLossShelfMinDb = -40.0;
inline constexpr double kLossBankCrossfadeS = 0.030;

inline constexpr double kTapeCoatingThicknessM = 12e-6;
inline constexpr double kTapeHeadGapM = 3e-6;

inline constexpr std::array<double, 5> kTapeSpeedsIps = {1.875, 3.75, 7.5, 15.0, 30.0};

inline constexpr std::array<double, 5> kHeadBumpIps = {1.875, 3.75, 7.5, 15.0, 30.0};
inline constexpr std::array<double, 5> kHeadBumpHz = {35.0, 45.0, 60.0, 80.0, 105.0};

inline constexpr std::array<double, 3> kAgeAxis = {0.0, 0.5, 1.0};
inline constexpr std::array<double, 3> kAgeSpacingUm = {5.0, 12.0, 25.0};
inline constexpr std::array<double, 3> kAgeHissDbfs = {-120.0, -78.0, -60.0};
inline constexpr std::array<double, 3> kAgeChewDepth = {0.0, 0.2, 0.6};
inline constexpr std::array<double, 3> kAgeDegrade = {0.0, 0.2, 0.5};

inline constexpr double kHissLpHz = 4000.0;

inline constexpr double kChewCleanScaleS = 1.5;
inline constexpr double kChewDegradedScaleS = 0.4;
inline constexpr double kChewVariance = 1.5;
inline constexpr double kChewTransitionS = 0.008;
inline constexpr double kChewPower = 2.0;
inline constexpr double kChewLpHz = 3000.0;

inline constexpr double kDegradeMinLpHz = 500.0;
inline constexpr double kDegradeGainDipDb = -1.5;
inline constexpr int kDegradeUpdateSamples = 1024;
 
}  // namespace pulp::signal::chardelay