Kalibrus Noise & Spectral Reference

Kalibrus is a calibrated acoustic reference generator, an expressive note-tracked noise synthesizer, and a modular CV modulation source for the Reason Rack.

Driven by a 32-bit floating-point xoshiro256++ core with 64-bit state registers, Kalibrus generates non-looped White, Pink (−3 dB/oct), and Brown (−6 dB/oct) noise fields in real time with true decorrelated stereo imaging (r < 0.005) and zero sample latency. Paired with 24 dB/octave Butterworth filters and a Mid/Side spatial matrix, it functions equally as a surgical mixing diagnostic tool and a playable analog-style synthesizer voice.

Use it to calibrate monitor acoustics, check room modes, execute pink-noise mix referencing, play 1V/Oct melodic noise patches from your keyboard, or drive modular CV rigs with continuous and sampled random voltages.

Three Studio Roles in One Foldable 2U Chassis

1. Calibrated Acoustic & Mixing Reference: Generate precision Pink (−3 dB/oct), White (0 dB/oct), and Brown (−6 dB/oct) spectra calibrated to a −18 dBFS True RMS standard. Cascaded 24 dB/oct Butterworth high-pass and low-pass filters isolate critical frequency bands (sub-bass rumble, midrange mud, vocal sibilance) and sweep room nodes.
2. Expressive Playable Noise Synthesizer: Connect MIDI or Gate/Pitch CV to play Kalibrus as an instrument. Features 1V/Oct keyboard pitch tracking with last-note priority, dynamic velocity response, MIDI Sustain Pedal (CC 64) support with selective release, and smooth quadratic bandwidth narrowing via Mod Wheel (CC 1) and Expression Pedal (CC 11).
3. Modular CV Modulation & Randomization Hub: Drive external Reason devices with continuous bipolar [−1.0V, +1.0V] post-filter spectral Noise CV and a gate-triggered Sample & Hold CV output. External stereo audio passes through cleanly at bit-identical unity gain, allowing you to sum calibrated noise directly over live mixes.

Key Features & Architectural Highlights

• 32-bit Floating-Point Xoshiro256++ Core: Dual independent PRNG generators with 64-bit state and uniform chi-square distribution (p > 0.05). Uncorrelated Left and Right noise fields with zero sample looping or phase cancellation.
• Cascaded 24 dB/octave Butterworth Filters: 4th-order biquad filters deliver steep rolloff curves across 20 Hz – 20 kHz with zero digital cramping at Nyquist.
• Mid/Side Spatial Matrix: Discrete M/S encoder/decoder with variable Stereo Width (0% mono to 200% ultra-wide) and level-invariant True Stereo Balance Law that conserves acoustic energy across the panorama.
• Calibrated True RMS & Peak Telemetry: Dual 20-segment calibrated LED ladder meters providing instantaneous 0 ms peak response and −24 dB/s leaky peak-hold at 60 FPS, referenced directly to faceplate dB markings.
• DAW Transport Sync & Manual Override: Set to AUTO to run noise synchronously during sequencer playback and recording, or switch to MAN for continuous hands-on bench testing.
• Dual-Mode Level CV Modulation: A 2-position trench slider switches rear Level CV behavior between an exponential VCA envelope follower (for percussion hits and ducking) and a linear AM tremolo modulator.
• Compact Folded Mastering Strip: Collapses into a space-saving 1U strip with active patch browsing, filter cutoffs, stereo balance, and output level controls.
• 35 Curated Factory Presets: 27 specialized patches categorized across Acoustic Calibration, Diagnostic Bandpass, Room Mode Probes, Modular S&H Textures, and Expressive Synthesis, plus 8 quick starter patches.

Technical Specifications

• Device Format: 2U Rack Extension (with full-function 1U compact folded strip)
• PRNG Engine: Dual 32-bit floating-point xoshiro256++ (Period 2^256 − 1)
• Cross-Correlation: r < 0.005 (Independent Left & Right channels)
• Oversampling: 2x polyphase precision core (0 samples latency, > 70 dB stopband rejection)
• Filter Topology: Cascaded 4th-order 24 dB/octave Butterworth (Nyquist-linearized)
• Reference Standard: −18.00 dBFS True RMS
• Rear Connections: Balanced L/R Audio Inputs (Thru/Summing), L/R Audio Outputs, Sequencer Pitch & Gate In, Gate Out, Bandwidth CV In, HPF CV In, LPF CV In, Level CV In, Continuous Noise CV Out, Gate-Triggered S&H CV Out