What is Audio Mastering?
Mastering is the final step in music production — the process of preparing a mixed track for distribution. It involves EQ balancing to ensure your song translates well across all playback systems (earbuds, car speakers, studio monitors), dynamic range compression to create consistency and punch, loudness normalization to meet streaming platform standards (typically -14 LUFS), and true peak limiting to prevent clipping.
Professional mastering studios charge hundreds of dollars per track. This tool gives you access to a production-grade mastering chain — multiband compression, harmonic exciter, transient shaping, stereo enhancement, LUFS normalization, and true peak limiting — completely free, running entirely in your browser.
How to Master Your Music
1. Upload Your Track
Drag and drop or click to upload an MP3, WAV, FLAC, M4A, or AAC file (up to 250 MB). Your file stays on your device — nothing is uploaded to a server.
2. Choose a Preset & Adjust Intensity
Select from 5 mastering presets: Balanced (any genre), Warm (soul/R&B/jazz), Bright (acoustic/pop), Punchy (rock/hip-hop), or Bass Heavy (EDM/trap). Use the intensity slider to fine-tune how aggressively the processing is applied.
3. Preview, Compare & Download
Click Preview to hear your mastered track. Use A/B comparison to switch between the mastered and original versions with level matching. When you're satisfied, click Download to save your mastered track as a WAV file.
Mastering Presets Explained
Balanced
Transparent mastering that works for any genre. Gentle EQ shelves, light compression, and standard -14 LUFS targeting. Start here if you're unsure which preset to use.
Warm
Analog-inspired warmth with boosted lows, gentle high rolloff, and tape-style saturation. Ideal for soul, R&B, jazz, and anything that benefits from a vintage feel.
Bright
Crisp clarity with enhanced highs and presence. The exciter adds air and sparkle. Perfect for acoustic music, pop, and tracks that need to cut through.
Punchy
Aggressive compression with scooped mids for maximum impact. Louder target (-12 LUFS) with stronger limiting. Built for rock, hip-hop, and high-energy genres.
Bass Heavy
Sub-focused mastering with significant low-end boost, bass mono for tight low frequencies, and warm saturation. Designed for EDM, trap, and bass-driven music.
Intensity Control
Every preset responds to the intensity slider (0.0–2.0). Light (0.5) applies subtle polishing. Normal (1.0) is the intended preset strength. Heavy (1.5+) pushes processing for a more aggressive master.
The Mastering Chain
This tool applies a 12-stage professional mastering chain to your audio:
EQ & Tone Shaping
5-band parametric EQ sculpts the frequency balance — adding warmth, presence, or air depending on your preset. High-pass and low-pass filters clean up sub-bass rumble and ultrasonic content.
Compression & Dynamics
Multiband compression controls dynamics independently across frequency bands, creating a tight, controlled sound without squashing transients. A dynamic processor reduces harshness.
LUFS Normalization
Your track is normalized to the target loudness level using ITU-R BS.1770-4 compliant LUFS measurement. This ensures your music plays at the right volume on Spotify, Apple Music, YouTube, and other platforms.
Limiting & Protection
A soft clipper shaves peaks gently, followed by a true peak limiter with lookahead and 4x oversampling. This prevents clipping while preserving transient clarity.
Mastering FAQ
What audio formats can I master?
You can upload MP3, WAV, FLAC, M4A, and AAC files up to 250 MB. The mastered output is downloaded as a high-quality WAV file.
Is my audio uploaded to a server?
No. Everything runs 100% in your browser using the Web Audio API. Your audio files never leave your device — no uploads, no server processing, complete privacy.
What does mastering do to my track?
Mastering applies a professional-grade signal chain to your audio: EQ balancing, multiband compression, stereo enhancement, LUFS loudness normalization, and true peak limiting. The result is a louder, more polished, and more consistent-sounding track.
Is this really free?
Yes, completely free. No account required, no downloads, no watermarks, no limits on file size or number of uses. Just open the page, drop in your audio, choose a preset, and download.
How does the A/B comparison work?
The A/B toggle lets you switch between your mastered track (A) and the original (B) during playback. The original is gain-matched so you can hear the tonal and dynamic differences without being fooled by volume changes.
What is the intensity slider?
The intensity slider controls how strongly the mastering preset is applied. At 0.0 (Light), effects are barely noticeable. At 1.0 (Normal), you get the preset as designed. At 2.0 (Heavy), effects are doubled for more aggressive processing.
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