Caustic 3

Caustic 3 is a music production tool that simulates the architecture of rack-mount synthesizers and sampling equipment, designed to run efficiently on mobile devices. The app centers on a modular rack capable of hosting up to 14 synthesis and processing machines, each fully routable into a mixer system. This hardware-inspired architecture lets users combine different sound sources and effects processing in any configuration, mirroring the flexible, patch-based design of analog synthesizer studios.

The synthesis engines available include Subsynth, a virtual analog subtractive synthesizer capable of producing traditional synth tones through oscillator and filter manipulation. PCMSynth is a multi-sample wave synthesizer that loads samples and soundfonts for playback and real-time manipulation. BassLine provides monosynth functionality inspired by the Roland TB-303, suited for bass lines and single-note melodic sequences. BeatBox functions as an 8-channel sampling drum machine for constructing drum patterns and percussion arrangements. PadSynth generates sustained harmonic tones for pads and atmospheric textures through harmonic table synthesis. 8BitSynth uses equation-based synthesis to create algorithmic and retro chip-tune-style tones. Modular offers a fully configurable and routable synthesizer for custom signal path design and advanced sound manipulation. Organ simulates a Hammond-style tonewheel organ with rotary speaker effects for classic organ sounds. Vocoder applies 8-band harmonic vocoding to process external audio sources. FMSynth implements 3-operator FM synthesis in the style of Yamaha DX synthesizers. KSSynth uses Karplus-Strong string modeling algorithms to generate string, plucked, and resonance sounds.

Each machine in the rack can host up to two effects drawn from a palette of 16 effect types. In addition to per-machine effects, the mixer desk includes global Delay and Reverb processors that affect the entire mix. The master section provides parametric EQ and a limiter for final mastering and loudness management. Most parameters support automation through dedicated editors that allow users to shape automation curves over time, enabling dynamic parameter changes at any point during a song.

The song sequencer allows users to arrange patterns into complete musical compositions. Users can record samples directly within the app, which can then be assigned to the PCMSynth, BeatBox, or Vocoder machines for further processing and playback. The app accepts uncompressed WAV files in 8-bit, 16-bit, 24-bit, and 32-bit formats at any sampling rate. PCMSynth also supports SoundFont .sf2 files, SFZ instruments, and FL Studio mobile instruments distributed as .instr or .ZIP files, substantially expanding the available sound sources beyond native engines.

Hardware controllers can be integrated via USB MIDI. Class-compliant USB MIDI controllers are supported on devices running Android 3.2 or later with USB host mode, connected through a USB OTG cable. This integration allows external keyboards and controllers to trigger and manipulate sounds in real time, enabling hardware-centric workflows and tactile control on mobile platforms.

Caustic 3 operates in two distinct modes: a demo version and a paid full version. The demo version has no time limit and allows complete experimentation with all synthesis and effects tools, though it disables song saving and export functionality. When the app closes, the current session is automatically saved, preventing accidental loss of work in progress. The full version is unlocked through purchase of the Caustic Unlock Key, which enables the ability to save songs and export to WAV and Ogg audio formats, as well as export MIDI data for integration with other music applications.

Tutorial videos and an online manual within the app provide guidance for learning the synthesis engines and sequencer workflow. Project files are stored on user-accessible storage, enabling straightforward management through the device's file system. The app requires a minimum processor speed of 1GHz with ARMv7 architecture and a minimum screen resolution of 800 by 480 pixels; audio output requires headphones or external speakers connected to the device.