MJSFX

Sounds and effects design studio

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MJSFX is a free, native macOS sounds and effects design studio. Start from a generator (lasers, explosions, blips, hits, etc) then build with layered oscillators, each with its own pitch sweep, envelope, and filters. Chain reverb, delay, distortion, bitcrush, and more per layer or across the whole sound, plus LFOs that can modulate knobs, including other LFOs. Everything exports to WAV, including retro formats like 22kHz/8-bit and per-layer stems. Sounds are repo-friendly JSON files as are all configuration files. It has extensive MIDI hardware support with soft pickup and per-controller profiles, a built-in library with folders and filtering, workspaces, a live "Sound Portrait" visualization drawn from real engine output, and twenty themes plus a browser-based theme builder. No in-app AI, but the direct download (and homebrew) version ships with an MCP server. Docs on the site. No ads, no telemetry, and you own everything you make. Requires Apple Silicon and macOS 14+.

Design Helpers IDE MCP

MJSFX is a free native macOS studio for designing and exporting sounds and effects.

for: Game developers and sound designers using macOS Apple Silicon.
pricing: free

works withmacOS 14+Apple Silicon

Key features

8 features of MJSFX

Generators — Start from curated sound generators like lasers, explosions, and blips.
Layered Oscillators — Stack multiple oscillators, each with independent pitch, envelope, and filters.
FX & LFOs — Apply up to 15 effects and modulate any knob with LFOs, including nested LFOs.
MIDI Hardware Support — Map knobs, faders, pads and save per-controller profiles for hands-on control.
Sound Portrait Visualization — Live waveform, amplitude and pitch-as-color view updates in real time.
Export Options — Export drop-in WAVs at 44.1/22/11 kHz, 16/8-bit and per-layer stems, including retro formats.
Theme Builder — Choose from 20 built-in themes or create custom themes via a browser builder.
AI Design via MCP Server — Direct-download version includes an MCP server to let Claude generate sounds from plain language.