FAQ
The nerdy details about what happens to your audio.
MASTERING
What actually happens to my track?
Your track goes through a multi-stage pipeline: EQ matching (shapes your frequency spectrum to match a reference or genre profile), multiband compression (treats lows, mids, and highs separately), stereo width adjustment, and loudness targeting to hit a specific LUFS value. For example, if your mix sounds dull compared to a reference, the EQ boosts the highs to match that brightness.
What's the difference between Reference and Profile mode?
Reference mode uses another track as a tonal model — your song ends up with a similar frequency balance. Profile mode uses a pre-computed spectral shape averaged from well-mastered tracks in a genre. For example, the "ambient_piano" profile gives you the frequency balance of polished ambient tracks without needing a specific song as reference.
What does the Width knob do?
It amplifies or reduces the Side channel (the difference between left and right). 1.0 means no change, above 1 makes the stereo image wider, and 0 collapses to mono. At 1.5, reverb and panned elements feel noticeably wider. At 0.5, everything tightens toward the center.
What's LUFS and why does it matter?
LUFS (Loudness Units Full Scale) is the standard for measuring perceived loudness. Spotify normalizes to -14, YouTube to -13, Apple Music to -16. The master targets whatever value you set so your track plays at the right level without the platform turning it down.
Does mastering add compression?
Yes, 3-band: lows get gentle compression to preserve punch, mids stay transparent, and highs are controlled to tame sibilance. After that, a limiter catches anything that would exceed 0dB. If your drums are poking out, the compressor tames the peaks while keeping the groove intact.
MIC DIAGNOSTICS
What does the analyzer check?
Nine things: input level, noise floor, signal-to-noise ratio, proximity effect (boom), sibilance, vocal presence, plosives, resonances, and spectral tilt. For example, if you're too close to the mic, it flags "proximity effect" — your voice sounds boomy below 200Hz.
What's "Apply & Download"?
It applies a corrective chain to your audio: noise gate, parametric EQ, compressor, and limiter. You get back a processed WAV file. Your raw recording with room noise and boomy lows comes back clean, balanced, and broadcast-ready.
Neutral vs Podcast — what's the difference?
Neutral applies minimal corrections — only what the diagnostic detected. Podcast goes full broadcast: double highpass, 2-stage compression, mud and boxiness cuts, presence boost, and air boost. Neutral is "fix my problems." Podcast is "make me sound like NPR."
CREDITS & KO-FI
How does the free tier work?
You get 5 masters and 10 mic diagnostics per week on a rolling 7-day window. It resets automatically. No account required, no credit card.
How do credits work?
A Ko-fi donation converts to lifetime credits. $1 gives you 5 masters. Credits kick in after you exhaust the weekly free tier. They never expire — $3 gets you 15 masters you can use this month or in 2028.
What if I run out?
The header shows a "Get more" link to Ko-fi. Or just wait for the next weekly reset.
TECHNICAL
What formats are supported?
Input: MP3, WAV, FLAC, OGG, AIFF, and 20+ more — anything FFmpeg and libsndfile can decode. Mastering output is MP3 at 320kbps. Mic diagnostics output is lossless WAV.
Do you keep my audio?
No. Audio is processed in a temporary directory that gets deleted immediately after. There is no persistent audio storage. The database only stores metadata — profile used, duration, LUFS result.
Is there a file size or length limit?
50MB upload limit, 10 minutes maximum duration. Processing times out after 2 minutes.
What quality is the output?
Mastering: MP3 320kbps (highest quality lossy). Mic diagnostics: uncompressed WAV (lossless). There's no double encoding — the master exports directly from the processing pipeline.