# Edward Boraas: Reason Rack Extensions & Audio DSP Documentation > Full-text technical documentation, engineering specifications, DSP architecture notes, and signal flow guides for Edward Boraas's Reason Rack Extensions and audio software. - Site: https://audio.boraas.ca - Developer: Edward Boraas - Contact & Store: https://www.reasonstudios.com/shop/browse/?developer=Edward%20Boraas - GitHub: https://github.com/edboraas --- ## About Edward Boraas & DSP Architecture Philosophy Edward Boraas is an independent software developer and audio engineer specializing in precision acoustic reference instrumentation, analog-modeled audio processors, and modular sound-design tools for Reason Studios' Reason DAW and Reason Rack Plugin. ### Core Architecture Invariants 1. **Pure Standard ISO C++17 Signal Processing**: All audio DSP algorithms, mathematical generators, state machines, and filter topologies are implemented in standard C++17 completely decoupled from host SDK headers. 2. **Double-Precision / 32-bit Floating-Point Computation**: Audio pipelines execute with full 32-bit floating-point precision, ensuring internal headroom far exceeding physical analog noise floors (-144 dBFS). 3. **Cascaded Analog-Modeled Filter Topologies**: Multi-order Butterworth and Kellet filter topologies are linearized at the Nyquist frequency to eliminate digital warping and preserve analog-smooth cutoff slopes up to 20 kHz. 4. **Zero-Latency Polyphase Oversampling**: Signal processing paths employing non-linear saturation or steep band-limiting utilize polyphase decimation and interpolation with 0 samples of host buffer latency and > 70 dB stopband rejection. 5. **Deep Modular Control Voltage (CV) Integration**: Every instrument and processor provides comprehensive rear-panel CV patchbays with standard 1V/Oct pitch tracking, gate routing, bipolar modulation, and sample & hold telemetry. --- ## Products & Rack Extensions ### Kalibrus (2U Rack Extension) **Tagline**: Precision Acoustic Reference, Expressive Noise Synthesizer & Modular CV Source **Category**: ACOUSTIC REFERENCE & SYNTH **Product ID**: `ca.boraas.Kalibrus` **Version**: 1.0.1 **Status**: shop **Canonical URL**: https://audio.boraas.ca/devices/kalibrus/ #### Summary Three-in-one laboratory-grade acoustic reference, playable noise synthesizer voice, and modular CV modulation engine. Combines a 32-bit floating-point Xoshiro256++ core, cascaded 24 dB/octave Butterworth filter topology, and 2x polyphase oversampling with optional transport synchronization, stereo audio passthrough and linear summing inputs, True Stereo Balance Law, 20-segment calibrated RMS/Peak telemetry at 60 FPS, 1V/Oct keyboard pitch tracking, dynamic velocity sensitivity, Mod Wheel passband narrowing, comprehensive rear CV I/O with continuous Noise and S&H CV out, and 35 curated presets (27 organized across 5 specialized categories, plus 8 instant quick starter patches). #### Key Features - 32-bit Floating-Point Xoshiro256++ Core - Cascaded 24 dB/octave Butterworth Filter Topology - 2x Polyphase Oversampling - True Stereo Balance Law - 20-Segment Calibrated RMS/Peak Telemetry - White, Pink (−3 dB) & Brown (−6 dB) Spectra - Transport Sync & Manual Override - Stereo Audio In Passthrough & Summing - 1V/Oct Tracking & Dynamic Velocity - Full Modular CV I/O Matrix & S&H Out - 35 Curated Presets (5 Categories + 8 Quick Starters) #### Technical Specifications - **Manufacturer**: Edward Boraas - **Form Factor**: 2U Full / Folded Strip with active controls - **PRNG Engine**: Dual 32-bit floating-point Xoshiro256++ core (Period 2^256 - 1) - **Cross-Correlation**: r < 0.005 (Independent Stereo Channels) - **Oversampling Core**: XO-24 Polyphase Precision Core (2x polyphase oversampling, 0 samples latency, > 70 dB stopband rejection) - **Filter Slopes**: Cascaded 24 dB/octave Butterworth filter topology (Nyquist-linearized, 4th-order) - **Calibration Level**: -18.00 dBFS True RMS Reference - **Balance Law**: True Stereo Balance Law (0 dB Center / Level Invariance, Sinusoidal Attenuation) - **Keyboard Tracking**: 1V/Oct Pitch Tracking (Last-Note Priority) - **Stereo Audio I/O**: Balanced/Unbalanced L/R Audio In (Passthrough & Summing) & L/R Audio Out - **Transport Sync**: AUTO Mode (Synchronized to DAW Playback with Manual Engage Override) - **Metering**: Dual Stereo 20-Segment Calibrated RMS/Peak Telemetry (-24 dB/s Leaky Peak-Hold at 60 FPS) - **Performance Modulation**: MIDI Sustain Pedal (CC 64) with selective release, Mod Wheel (CC 1) & Expression Pedal (CC 11) passband narrowing - **Modular CV Connectivity**: Pitch In, Gate In, Gate Out, Bandwidth (Mod Wheel) In, HPF/LPF In, Level In (Dual VCA/Tremolo with 2-position trench slider), Bipolar Noise CV Out, Gate-Triggered S&H CV Out - **Factory Soundbank**: 35 Curated Presets (27 across 5 Functional Categories + 8 Quick Starters) - **SDK Target**: 4.6.0 (Reason 10.1+, Apple Silicon & x64, Plugin & DAW) #### Detailed Documentation & Signal Flow ## Laboratory Precision in the Reason Rack **Kalibrus** is engineered as three distinct studio tools in one versatile rack unit: a calibrated acoustic and mixing reference generator, an expressive note-tracked noise synthesizer voice, and a modular CV modulation and randomization engine. It combines laboratory-grade test signals, a playable noise instrument, and modular CV generation in a single Rack Extension. Unlike basic software noise generators that rely on short looping samples or low-entropy pseudo-random routines, Kalibrus features a pure C++17 DSP engine driven by a **32-bit floating-point Xoshiro256++ core** running dual uncorrelated 64-bit state generators (r < 0.005). This guarantees mathematically pure spectral energy distribution across the entire audible spectrum (20 Hz – 20 kHz) with zero audible periodicity or repeating artifacts. Coupled with a **cascaded 24 dB/octave Butterworth filter topology** and zero-latency **2x polyphase oversampling**, high-pass and low-pass cutoffs remain completely free from digital Nyquist cramping, preserving analog-smooth filter slopes up to 20 kHz. --- ## Noise Spectra ### White Noise (Flat Power Density) Uniform floating-point mapping with equal power across all frequency bands. Essential for testing microphone responses, converter frequency linearity, comb-filtering diagnostics, and synthesizing snappy percussion transients. ### Pink Noise (−3 dB/octave) Synthesized using an optimized 6-pole (+1 FIR) Paul Kellet IIR filter topology. Maintains tight ±0.3 dB spectral linearity across the full 20 Hz – 20 kHz acoustic spectrum. Calibrated to a bit-exact -18.00 dBFS True RMS reference at unity gain for instantaneous K-System monitor alignment and frequency-masking mix balancing. ### Brown Noise (−6 dB/octave) Synthesized via a first-order leaky integrator IIR filter with integrated high-pass DC bias blocking. Delivers deep, organic low-frequency acoustic energy ideal for subwoofer tuning, room boundary resonance testing, and beefing up 808 sub-bass lines. --- ## Transport Synchronization & Audio Insert Workflow Kalibrus integrates directly into live mixing and mastering workflows without requiring external auxiliary mixers or routing workarounds: - **Transport Synchronization & Manual Override**: The front-panel features a unified Engage control hierarchy under a centered `ENGAGE` header: an illuminated halo push button with bold intaglio `MAN` cap serves as an independent manual override latch for continuous room tuning and background pink noise mix balancing, alongside an illuminated cyan `AUTO` button that locks noise generation directly to Reason's transport state (emitting noise automatically during playback and silencing cleanly upon stopping via smooth 50 ms Hann raised-cosine enveloping). - **Stereo L/R Audio Passthrough & Linear Summing**: Rear stereo inputs labeled `Inputs (Thru Raw)` allow Kalibrus to be inserted directly between a mix bus or mastering chain and the hardware output device, which is especially indispensable in Reason Free where an auxiliary line mixer is not provided. When Kalibrus is idle or silent, incoming audio passes through with bit-identical fidelity at ~0% CPU overhead. When noise is emitted, incoming audio is cleanly summed (`Sum: Raw Input + Noise`) at unity gain. - **True Stereo Balance Law & Mid/Side Imaging**: Employs a level-invariant **True Stereo Balance Law** (0 dB Center) with smooth sinusoidal attenuation on the opposite channel when panned. This maintains bit-exact -18.00 dBFS True RMS on the isolated channel without pan-law level boost (+3.01 dB), making single-monitor SPL calibration as simple as panning hard Left or Right without recalculating gain offsets. Paired with continuous Mid/Side stereo width scaling from 0% (pure mono) through 100% (standard stereo) up to 200% (hyper-wide side energy). - **20-Segment Calibrated RMS/Peak Telemetry**: Front-panel dual 20-segment true-power RMS LED ladders with instantaneous peak-hold attack and -24 dB/s calibrated decay at 60 FPS dynamic decimation monitor Left and Right channels independently, providing laboratory-grade stereo telemetry and headroom verification. --- ## Ergonomic Hardware Interface Architecture The interface provides immediate tactile control across both full and compact folded rack views: ### Full 2U Rack Panel - **Bay 1 (Power & Transport)**: Textured console tape strip, bold intaglio KALIBRUS nameplate, illuminated cyan `AUTO` transport sync button, illuminated halo push button with bold intaglio `MAN` cap centered under the `ENGAGE` header, and a dedicated cyan `NOTE` jewel lamp positioned below the Kalibrus emblem reflecting active keyboard and sequence triggering in real time. - **Bay 2 (Noise Color & Spectral Sculpting)**: Smooth vertical **trench slider** with illuminated LED halo indicating active noise color (Brown, Pink, or White), flanked by large anodized aluminum rotary dials with radiant pointer halos governing the cascaded 24 dB/octave Butterworth high-pass (20 Hz – 20 kHz) and low-pass (20 Hz – 20 kHz) cutoffs. - **Bay 3 (Spatial Processing)**: 3-position vertical trench slider with crisp white halo selecting stereo routing (`[DUAL | STR | MONO]`), paired with continuous `WIDTH` (0% – 200%) and detented `BALANCE` controls. - **Bay 4 (Master Output & Telemetry)**: Anodized master `NOISE LEVEL` dial with 0 dB center detent, and dual vertical **20-segment calibrated RMS/Peak telemetry** ladders (−48 dBFS to 0 dBFS) with amber RMS bars and crimson peak-hold indicators. - **Chassis Construction**: Anodized aluminum chassis fitted with Canadian Robertson square-drive countersunk bolts and vintage-style console labeling tape. ### Compact Folded Mastering Strip When rack space in dense projects is at a premium, Kalibrus collapses into a streamlined folded strip maintaining full interactive control across four functional bays: - **Bay 1**: Identity tape, engraved nameplate, active `AUTO` / `MAN` push buttons, real-time `NOTE` jewel lamp, recessed acrylic patch display, and 4-quadrant tactile browse buttons. - **Bay 2**: Tactile backlit 3-position **chiclet radio buttons** (`[BRN | PNK | WHT]`), compact `HIGH-PASS` mini dial (20 Hz), and `LOW-PASS` mini dial (20 kHz). - **Bay 3**: Tactile backlit **routing chiclet radio buttons** (`[MONO | STR | DUAL]`), compact `WIDTH` mini dial (0% – 200%), and `BALANCE` mini dial. - **Bay 4**: Master `NOISE LEVEL` mini dial and calibrated dual horizontal stereo RMS/Peak telemetry bars. --- ## Synthesis & Keyboard Tracking Kalibrus tracks keyboard pitch and MIDI dynamics for expressive sound design: - **1V/Oct Keyboard Pitch Tracking**: Connect MIDI keyboards or sequencer gates to pitch-track Kalibrus's filter passband center across the musical scale. Features last-note priority with pitch bend support for pitched noise percussion, tuned sub-bass tones, and wind-like melodies. Note triggering delivers full-bandwidth noise bursts at Mod Wheel = 0 shaped strictly by the front-panel HPF and LPF knobs across their entire travel without unexpected note-tracking bandpass collapse. When manual HPF is turned above the played note pitch (or LPF below it), the cascaded 24 dB/octave Butterworth filters form an inverted overlap, completely attenuating the signal to silence (< −100 dBFS) for precision acoustic isolation. - **Dynamic Velocity Sensitivity**: Triggered notes respond dynamically to MIDI velocity and analog Gate CV amplitude, shaping transient burst attacks for snare layers, clap synthesis, and rhythmic accents. - **MIDI Sustain Pedal Support (CC 64)**: Holding the sustain pedal latches the sounding noise voice and filter passband through note-off events with intelligent selective release, allowing musicians to sustain notes hands-free while adjusting front-panel filter and spatial dials. - **Mod Wheel & Expression Pedal Bandwidth Control**: Mod Wheel (CC 1), Expression Pedal (CC 11), and rear Bandwidth (Mod Wheel) CV smoothly narrow the cascaded Butterworth filter bandwidth around the tracked pitch using continuous exponential tapering (w = 121 − 2m octaves) down to a focused 2-semitone passband (1/12 octave) at full throw. A smoothed quadratic gain compensation curve (+6.8 dB at full throw) ensures transparent perceived peak loudness without mid-throw volume bumps. - **Release Fade Cutoff Latching**: Filter cutoffs and sounded pitches remain solidly latched through the 5 ms release fade, eliminating transient clicks upon note-off. --- ## Rear-Panel Modular CV Matrix Designed to integrate deeply into the Reason Rack's modular cabling environment, Kalibrus provides a complete rear-panel CV patchbay: - **Pitch CV In & Gate CV In**: Full 1V/Oct modular note pitch and gate triggering with wide dynamic sensitivity (> 0.02 V). - **Gate Out CV Output**: Outputs standard +1.0V Reason Gate CV triggered from MIDI keyboard and sequencer playback (scaled by note velocity) for driving downstream envelopes directly, or acts as a direct pass-through relay when an external cable is patched into Gate In. - **Bandwidth (Mod Wheel) CV In**: Dedicated 0 – 10V modulation input allowing external LFOs, sequencers, or mod wheels to dynamically narrow or widen the tracked passband width Q. - **HPF & LPF Cutoff CV Inputs**: Independent CV inputs with dedicated rear attenuator trim pots spanning up to 10 octaves, enabling full-spectrum (20 Hz – 20 kHz) envelope sweeps and direct cutoff modulation. - **Level Modulation Subsystem (Level CV In, 2-Position Trench Slider & Trim)**: Dual-mode voltage-controlled amplifier and amplitude modulator framed by technical bracket rails. The 2-position vertical trench slider toggles between VCA mode (crisp white indicator) and Tremolo mode (warm amber indicator). In VCA mode, accepts unipolar envelopes with positive trim opening dynamically from silence up to front-panel level, and negative trim delivering aggressive cubic sidechain ducking (-18.1 dB at half CV). In Tremolo mode, delivers clean, symmetric linear amplitude modulation for bipolar LFOs with phase inversion. - **Continuous Noise CV Out**: Pure uncorrelated standard modular bipolar [-1.0V, +1.0V] random control voltage tapped post-filter (pre-VCA) from rear output jacks. Directly shaped by front-panel Noise Color, cascaded 24 dB/octave HPF/LPF cutoffs, and 1V/Oct keyboard pitch tracking (enabling real-time acoustic sculpting from high-frequency white flutter down to smooth Brownian drift) while remaining continuous and fully independent of Master Level attenuation and Engage/Mute states. - **Gate-Triggered Sample & Hold (S&H) Stepped CV Out**: Produces stepped, held standard bipolar [-1.0V, +1.0V] voltages sampled directly from the filtered noise bus on each incoming note strike or gate edge from rear jacks, ideal for generative modular melodies, rhythmic step modulation, and chromatic pitch quantization. - **AC Mains Power Receptacle**: Studio-standard C14 IEC power connection with heavy rubber power cable. - **Rear Chassis**: Studio-grade rear rack ears with console marking tape. --- ## Curated Factory Preset Library (35 Presets / 5 Categories + 8 Quick Starters) Kalibrus ships with 35 factory presets (27 organized across 5 functional subdirectories, plus 8 glanceable root quick presets including `Quick - Pink -18 dBFS.repatch` enabling instant single-click calibration and continuous whole-library `<` and `>` stepping across all subdirectories): 1. **Root Quick Presets** (8 Presets): Instant starter and reference configurations including `Quick - Pink -18 dBFS`, `Quick - White Flat`, `Quick - Brown Sub`, `Quick - AES-SMPTE`, `Quick - Speech Ref`, `Quick - Sub Probe`, `Quick - Vinyl Bed`, and `Quick - Dual Mono`. 2. **`01 Reference & Calibration`** (10 Presets): Bob Katz K-System RMS monitoring references (`K-20`, `K-14`, `Pink Stereo -12dB`, `True RMS Pink Reference -18dBFS`), official AES/SMPTE Band-Limited Pink Noise (500 Hz – 2 kHz), EBU R128 (-23 dB CAL), Brown Noise Sub Reference (-6 dB/octave), White Noise Reference (Flat 0 dB), phase coherence checks, and dual-mono decorrelated room probe references. 3. **`02 Mixing & Diagnostics`** (5 Presets): Surgical frequency-masking diagnostic tools and auditory palate cleansers including Pink Noise Mix Balancing (-18 dB CAL), Lower-Mid Palate Cleanser (200 Hz – 500 Hz), Mid-Band Speech Reference (300 Hz – 3 kHz), Upper-Mid Ear Reset (4 kHz – 8 kHz), and Top-End Air Reset (10 kHz – 20 kHz). 4. **`03 Acoustic Probes`** (4 Presets): Low-frequency room mode and boundary diagnostic tools for Subwoofer Tuning (20 Hz – 120 Hz), Sub-Bass Room Mode Probe (40 Hz – 100 Hz), Subwoofer Crossover Alignment (60 Hz – 100 Hz), and Fletcher-Munson human ear fatigue analysis (1 kHz – 3.5 kHz). 5. **`04 Textures & Modulation`** (4 Presets): Analog tape hiss beds (`Tape-Band Noise Floor (-42dB)`), Lo-Fi Vinyl Surface Bed (-36 dB), Subtle Digital Dither Bed (-60 dB), and modular clock randomizers (`Modular Clock Randomizer (S&H CV)`). 6. **`05 Performance & Layering`** (4 Presets): White Noise Build-Up Riser (Mod Wheel passband swell), key-triggered snare/clap burst layers, sub-bass air weight for electronic kicks, and acoustic instrument breath chiff. --- ## Studio Documentation & Reference Guides Comprehensive operational manuals and reference guides are provided for studio engineers and sound designers: - **[Operation Manual & Studio Reference Guide](/devices/kalibrus/manual/)**: Detailed handbook covering full and compact folded hardware ergonomics, Xoshiro256++ PRNG mathematics, Butterworth filter cascades, Mid/Side matrix width processing, rear CV modulation matrix, Studio Monitor Alignment (83 dB(C) SPL standard), Pink Noise Mix Balancing, Subwoofer Crossover & Room Mode Detection, transient sound design recipes, and complete Reason Remote parameter maps. - **[Quick Start Guide & Modulation Reference](/devices/kalibrus/quick-start/)**: Focused 2-minute routing cheatsheet covering external envelope modulation (Sweeper, ECF-42, CV DADSR), intelligent release following, avoiding silent voice clamps, and Combinator 2 latching keyswitch architectures. --- ## System Requirements & Host Compatibility ### Supported DAWs & Plugin Hosts Edward Boraas's Rack Extensions run natively inside Reason and inside any standard digital audio workstation via the Reason Rack Plugin: - **Native DAW**: Reason Studios Reason 10.1 or later (Reason 10, 11, 12, 13+) - **Plugin Hosts (via Reason Rack Plugin)**: - Apple Logic Pro (AU) - Avid Pro Tools (AAX 64-bit) - Ableton Live (VST3, AU) - Steinberg Cubase / Nuendo (VST3) - PreSonus Studio One (VST3, AU) - Image-Line FL Studio (VST3) - Cockos Reaper (VST3, AU) - Bitwig Studio (VST3) ### Operating System Compatibility - **macOS**: macOS 10.13 High Sierra through macOS 14 Sonoma, macOS 15 Sequoia, and later. Native Apple Silicon (M1/M2/M3/M4) and Intel x64 architectures. - **Windows**: Windows 10 (64-bit) and Windows 11 (64-bit). --- ## Licensing, Delivery & Verification All commercial Rack Extensions developed by Edward Boraas are delivered and licensed through Reason Studios' proprietary digital distribution system: 1. Try before you buy: Free 30-day fully functional trial available through the Reason Studios Shop. 2. Installation: Managed directly via Reason Companion or the Reason Authorizer. 3. Official Developer Portal: [https://www.reasonstudios.com/shop/browse/?developer=Edward%20Boraas](https://www.reasonstudios.com/shop/browse/?developer=Edward%20Boraas)