Mastering is the final polish applied to mixed audio. This tool runs a chain of high-pass filter, compressor, loudness normalizer, and limiter to produce levels suitable for streaming or podcast platforms. It runs in the browser using ffmpeg.wasm, so no software installation is required, and multiple files can be processed in parallel.

Choosing a Preset

Streaming (-14 LUFS) matches the recommended loudness for Spotify, Apple Music, YouTube, and most streaming services. Loud (-9 LUFS) suits genres that need more volume, such as EDM, hip-hop, and rock. Podcast (-16 LUFS) is tailored for podcast and voice content. Studio (WAV) outputs a lossless file for further editing or delivery to a mastering engineer. Each preset differs in loudness target and limiter settings.

Output Format

WAV (pcm_s16le) is lossless and ideal for archiving or further editing. M4A (AAC) is smaller and convenient for streaming uploads. Use M4A for platform uploads and WAV when you need a master archive.

Processing Notes

Very long files (e.g., over an hour) or large batches may fail due to browser memory limits. Processing speed depends on CPU and file length. Keep the tab open until jobs complete. The cancel button stops in-progress jobs, but completed files remain available for download.

Tips

Ensure your mix is finished before mastering. Heavy clipping or noise is hard to fix with mastering alone. Try different presets to find the right fit, and consider exporting both streaming and loud versions. For complex projects, consider working with a professional mastering engineer.