Free Mastering Studio

Grumpy Music’s Mastering Studio is a free, browser-based tool for mastering AI-generated music. Users can load a track, audition six presets, compare before and after, and download a master without creating an account. Audio processing happens on their own device.

The simple view focuses on listening and choosing a sound. Opening a preset’s tool icon reveals the individual processors, with changes heard in real time.

Graphical EQ - Low-cut filter, low shelf, low-mid bell, presence bell and high shelf. Adjustable frequencies and gains, plus bandwidth for the bell filters.

Three-band dynamic EQ - Frequency, bandwidth, threshold, maximum reduction, ratio, attack and release for each band. Reduces selected frequencies when they become prominent.

Three-band compression - Independent low, mid and high compressors, each with threshold, ratio, attack and release. Adjustable crossover frequencies.

Stereo width - Narrow or widen the stereo image. A setting of 1 preserves the original width; 0 folds it to mono.

Output drive - Adjust the level entering the limiter to control loudness and how hard limiting works.

True-peak limiter - Adjustable output ceiling and release, with lookahead and reconstructed peak detection.

Bypass and reset controls — Enable or disable processing modules, bypass individual dynamic EQ/compressor bands, and reset each tool.