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SPECTRAL v2.4.0 — RB-420 Acid Tracker Workstation

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@EmergentMonk EmergentMonk released this 14 Jul 08:44
· 9 commits to main since this release
v2.4.0
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SPECTRAL v2.4.0 introduces RB-420 Acid Tracker Workstation 1.0: an original, zero-install browser instrument combining a dual-acid groovebox, algorithmic drum machines, visual pattern editing, deterministic and live loop recording, an Impulse-style tracker, and a seeded guitar/synth laboratory.

Open rb-420/index.html directly—no server, Node, npm, build system, framework, cloud service, or network connection required.

What’s new

RB-420 Groovebox

  • Two monophonic acid synthesizers
  • Sawtooth and square oscillators
  • Cutoff, resonance, envelope modulation, decay, accent, and level controls
  • Per-machine mute and solo
  • Sixteen-step note, accent, gate, and slide programming
  • Algorithmically synthesized 808-style and 909-style drum voices
  • Kick, snare, closed hat, open hat, clap, and rim lanes
  • Euclidean rhythm generator
  • Seeded pattern mutation
  • Master distortion, filter, delay, feedback, wet mix, and compression
  • Live oscilloscope and output meter

No commercial drum samples or proprietary instrument assets are included.

Pattern Master

The new Pattern Master replaces hardware-style pitch entry with a dedicated piano-roll editor for both acid synthesizers.

It supports:

  • Direct note placement and removal
  • Accent and slide programming
  • Step inspector
  • Pattern copy and paste
  • Transposition
  • Seeded variations
  • Open .rb420-pattern.json import and export

Dual-mode 30-second recorder

RB-420 provides two clearly separated recording contracts.

Deterministic Render

  • Freezes patterns, parameters, BPM, swing, seed, effects, tracker events, and sample identities
  • Produces fixed-frame stereo PCM16 WAV
  • Supports 44.1 kHz and 48 kHz
  • Supports durations from 1 to 30 seconds
  • Uses seeded noise and deterministic PCM synthesis
  • Exports a reproducibility recipe
  • Generates a stable PCM identity digest
  • Can send the resulting loop directly into the Tracker

This is a deterministic creative-render contract tied to the RB-420 renderer version. It is not presented as the stronger cross-runtime SPECTRAL Canonical Strict contract.

Live Performance Capture

  • Records the actual Web Audio performance
  • Captures knob movements, pattern changes, mutes, solos, and tracker playback
  • Automatically stops at the selected duration
  • Exports stereo PCM16 WAV
  • Can send the captured performance directly into the Tracker

Live recordings are intentionally take-specific and do not receive deterministic render recipes.

Impulse-style Tracker

A new eight-channel tracker provides a keyboard-oriented alternative to FastTracker-style composition.

Features include:

  • Eight tracker channels
  • 32- or 64-row patterns
  • Configurable rows per beat
  • Note, instrument, volume, and effect columns
  • Sixteen sample/instrument slots
  • QWERTY piano entry
  • PCM16 WAV import
  • Browser-decoded fallback for other supported audio formats
  • Direct Recorder and Sound Lab integration
  • Deterministic tracker-only loop rendering
  • Portable project storage with embedded PCM samples

Tracker effect codes are stored in project data for future expansion. Arbitrary Impulse Tracker effect commands are not yet executed.

Sound Lab

The new Sound Lab creates original deterministic guitar and synthesizer loops without bundled samples.

Included synthesis layers:

  • Karplus–Strong-style plucked guitar
  • Analog-style synth voice
  • Triangle-wave sub-bass
  • Seeded metallic/noise textures
  • Drive and stereo-space processing

Available generative styles:

  • Acid Rock
  • Machine Funk
  • Dark Country
  • Industrial
  • Tracker Core

Generated loops can be previewed, downloaded as WAV, or sent directly into the Tracker.

Project formats

RB-420 introduces open, inspectable formats:

.rb420.json                 Complete workstation project
.rb420-pattern.json         Acid pattern and parameters
.wav                        Stereo PCM16 audio
.recipe.json                Deterministic render recipe

Projects can embed PCM samples as base64, allowing complete sessions to remain portable as a single file.

Original ReBirth .rbs and Impulse Tracker .it compatibility are not falsely claimed. These are separate binary formats requiring independently tested import and export implementations.

Browser-native architecture

RB-420 follows the established SPECTRAL application philosophy:

  • no server
  • no localhost requirement
  • no Node or npm
  • no package manifest
  • no build or bundling step
  • no external framework
  • no CDN or remote assets
  • no telemetry or analytics
  • no cookies
  • no network client
  • no proprietary samples

All synthesis, sequencing, visualization, recording, project management, and export operations remain inside the browser.

Verification

The bundled browser-native suite is available at:

rb-420/tests/index.html

It covers:

  • repeatable deterministic PCM rendering
  • seed-sensitive output identity
  • exact PCM16 WAV encode/decode round trips
  • stable deterministic recipe identities
  • Sound Lab replay equivalence
  • malformed WAV rejection

The main application also performs a short deterministic render and WAV round-trip self-check during startup.

Repository updates

The root SPECTRAL README now:

  • lists six zero-install browser applications
  • adds RB-420 to Project Areas
  • includes the RB-420 application and test paths
  • links directly to the RB-420 documentation

Quick start

rb-420/index.html

Press PLAY once to initialize Web Audio, program a groove, render or record a loop, and send it to the Tracker.

Gremlin notes

  • Browsers require a user gesture before audio playback can begin.
  • Live Capture is intentionally affected by performance timing and browser audio scheduling.
  • Projects containing several embedded 30-second samples can become large.
  • Non-PCM audio formats pass through the browser’s decoder before being frozen into a sample slot.
  • Tracker effect codes are stored but not fully executed in v1.0.
  • Original .rbs and .it binary import/export are outside this release.
  • Deterministic recipes should retain the RB-420 application and renderer versions.

Links

Created by Trent Slade / QSOL-IMC.

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