Caustic 1.0: The Foundation

Core Release Metadata

• Official Release Date: 2011.

• Initial Build Number: 1 (v1.0.0).

• First Stable Public Build: 1.1.0 (Build 6).

• APK File Size: 5 MB.

• Monetary Cost (Historical): Approximately £2.49 / $4.00.

• Distribution Model: In-app purchase paradigm.

• Software Certificate: Signed by Rejean Poirier, SingleCellSoftware.

System Requirements & Architecture

• Minimum Operating System: Android 2.1 (Eclair MR1).

• Processor Architecture: ARMv7 (armeabi-v7a).

• Graphics Specification: OpenGL ES 1.0.

• Display Targets: Small, normal, and large screen densities at 160 DPI.

• Orientation: Hardcoded to landscape mode.

• Permissions: READ_EXTERNAL_STORAGE, WRITE_EXTERNAL_STORAGE, WAKE_LOCK, BILLING.

Audio Engine Specifications

• Processing Logic: Utilised a combination of 16-bit fixed point and floating-point mathematical routines.

• Audio API: Standard Android Java AudioTrack API.

• Performance: Characterized by high, hardware-dependent latency prior to the version 3.0 OpenSL ES implementation.

• Bit Depth Support: Restricted to 16-bit PCM WAV files for user samples.

• Sample Rate Support: 44.1 kHz (Note: Users reported the engine "did not like" 48 kHz files during this era).

The Initial Machine Rack

The version 1.0.0 rack was restricted to a specific pre-configured set of machines rather than a dynamic selection system.

• Subsynth (1 instance): The virtual analog core using subtractive synthesis. It featured dual oscillators, a resonant filter, and LFOs. In the initial prototype, the UI was described as "pretty ugly".

• Bassline (2 instances): Monophonic lead synthesizers loosely modeled after the Roland TB-303. It was limited to a 3-octave note range and featured a built-in 16-step pattern editor.

• Beatbox (1 instance): An 8-channel sample-based drum computer.

• PCMSynth (1 instance): A pulse code modulation sample player featuring a "weird double keyboard" UI layout.

Machine-Specific Logic & Constraints

• Envelope Mapping: Utilised linear knob mapping for ADSR envelopes (exponential mapping was not introduced until v1.3.0).

• Sample Management: Beatbox kits and PCMSynth presets did not "wrap" or internalise raw WAV data; presets contained only file path references to loose samples on storage.

• Beatbox Interaction: Samples were loaded into channels by long-pressing the "Play/Preview" button (changed to an ellipses button in version 2.1).

• Automation: Recording was possible in real-time within "Song Mode" only, with no provision to edit or view the resulting automation curves.

• MIDI Support: Restricted to basic Note On/Off messages; no support for Control Change (CC) or MIDI Learn was present.

Mixer & Effects

• Mixer Architecture: 7 strips (6 machine channels + 1 master section).

• Per-Channel EQ: Three-band EQ knobs (Bass, Mid, High).

• Effect Limits: Maximum of 2 insert effects per machine.

• Signal Flow: Serial path from top insert to bottom insert before reaching the mixer.

• Global Master Effects: Delay and Reverb.

Historical Context

• Development Origins: Conceived as a subtractive synthesis test prototype while the developer was learning synthesis.

• Naming History: Initially titled "No good reason" as a self-deprecating reference to Propellerhead Reason. The name "Caustic" was suggested by a friend to fit the "acid" techno aesthetic.

• Early Bugs: Specific reports included graphics memory leaks on NVidia Tegra-based hardware using Android 2.3 (Gingerbread).

Archival Gaps

• Specific internal build notes for patches between v1.1.2 and v1.2.0: Specific technical detail not documented in archived sources.

• The exact center frequencies for the v1.0 version of the 3-band EQ: Specific technical detail not documented in archived sources. (Note: Rej provided frequency data for the v3.1 EQ rewrite, but v1.0 specifications are missing).

• Total maximum sample length for PCMSynth in the 1.0 build: Specific technical detail not documented in archived sources.