What is Audio Mastering?
Mastering is the final step in music production, the process of preparing a mixed track for distribution. It means balancing the EQ so your song translates across every playback system (earbuds, car speakers, studio monitors), compressing the dynamics for consistency and punch, adding a little harmonic colour for weight, and limiting the peaks so nothing distorts.
Professional mastering studios charge hundreds of dollars per track. This tool gives you the core of that chain for free, running entirely in your browser: a high-pass filter, three bands of EQ, compression, harmonic saturation, and a limiter with a safety clipper that makes clipping impossible. Five presets get you started in one click, and all six sliders stay editable.
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. Pick a Preset, Then Fine-Tune
Start with one of 5 presets: Balanced (any genre), Warm (soul/R&B/jazz), Bright (acoustic/pop), Punchy (rock/hip-hop), or Bass Heavy (EDM/trap). Each one sets the six sliders for you: Low, Mid, and High EQ, plus Compression, Saturation, and Volume. Every slider stays editable, so you can adjust anything by hand afterwards.
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 Master Track, then download your master as MP3 (320kbps) or lossless WAV.
Mastering Presets Explained
Each preset is a starting point. It moves the six sliders to a setting that suits a style, and you can take it from there.
Balanced
Transparent polish that works for any genre. A touch of low and high shelf, light compression, and a hint of saturation. Start here if you are not sure which preset to use.
Warm
Analogue-inspired warmth: lows lifted, highs eased back, and a generous helping of saturation for tape-style thickness. Ideal for soul, R&B, jazz, and anything that benefits from a vintage feel.
Bright
Crisp clarity with the high shelf pushed up and the lows trimmed slightly, so the top end has room to breathe. Good for acoustic music, pop, and tracks that need to cut through.
Punchy
Heavy compression with scooped mids for maximum impact, plus extra volume and drive. Built for rock, hip-hop, and high-energy genres.
Bass Heavy
Sub-focused, with a big low shelf, mids pulled back to leave room, and warm saturation to keep the bottom end audible on small speakers. Designed for EDM, trap, and bass-driven music.
Or Go Custom
You do not have to use a preset at all. The six sliders are always live, and moving any of them simply drops the preset highlight. Low, Mid, and High run from -12 to +12 dB, Compression and Saturation from 0 to 100%, and Volume from -12 to +12 dB.
The Mastering Chain
Your audio runs through this chain live, updating as you move the sliders:
EQ & Tone Shaping
A high-pass filter clears out sub-bass rumble first. Then three EQ bands shape the balance: Low as an 80 Hz shelf, Mid as a 1 kHz peak, and High as an 8 kHz shelf, each adjustable by up to 12 dB in either direction.
Compression
A compressor evens out the loud and quiet moments. Higher settings tighten the track and lift its average level; lower settings leave more of the original dynamics intact.
Saturation
A waveshaper adds gentle harmonic colour, the analogue-style thickness that makes a mix feel fuller and louder without simply turning it up. It runs at 2x oversampling so the added harmonics stay clean.
Limiting & Clip Protection
A limiter catches the peaks that survive the chain, and a final safety clipper bounds the output by construction. Your file cannot reach the digital rails and distort, however hard you push the sliders.
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 polish chain to your audio: EQ balancing, compression, harmonic saturation, and peak-safe 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. Files up to 250 MB. No limit on the 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.
Can I adjust a preset after choosing it?
Yes. A preset is only a starting point: it writes the six sliders, and all of them stay editable. Move any slider and you are on your own settings, and the preset button simply stops being highlighted. Pick another preset any time to jump back to a known starting point.
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