/ Free online tool — Mono-compatibility checker
Drop a file.
Check it in mono.
Per-band phase analysis. See which frequencies collapse when your file is summed to mono. No upload. No sign-up.
Click or drop audio.
WAV, MP3, FLAC, OGG, M4A, or AAC. Stereo files only — mono input has nothing to check.
/ Method
How the mono-compatibility
checker works.
Method: cross-spectral coherence per frequency bin · Built by Sample Vault
The same per-band stereo analysis the desktop app runs across your library, in your browser.
/ 01 — Per-bin coherence
We compare left and right channel by channel, frame by frame, for every frequency bin. Bins where the two channels are in-phase add up cleanly when summed; bins where they're out-of-phase cancel.
/ 02 — Banded scoring
Per-bin scores are averaged into five mixing-relevant bands — sub-bass, bass, low-mids, mids, highs — and weighted by energy into a single overall score. That's the number you see at the top.
/ 03 — Why the bands matter
Sub-bass cancellation is the one to watch. Wide stereo bass can sound massive on headphones and disappear on a club sub. The per-band bars surface that asymmetry — overall might pass while sub-bass alone fails.
/ 04 — Fully local
The file never leaves your machine. Loads once, runs offline thereafter. Useful for unreleased material, label stems, and anything you can't put through a third-party service.
/ Across your library
From one file
to fifty thousand.
Checking one file is fine before a bounce. Checking every loop and stem in your library — and filtering for the ones that collapse in sub-bass — is the desktop app. Same engine, run across every folder you point it at.