Track check
Drop audio in and it reads the spectrum to work out what the file really is, then measures loudness on the same scale streaming services use. Catches upscaled rips that claim to be 320.
MP3, WAV, FLAC, M4A, OGG and AIFF. Browsers refuse AIFF outright, so that one is decoded here in the page instead. Files are read and analysed in this tab and never uploaded, so a whole folder is fine. Add several at once and they queue up.
A lossy encoder throws away everything above a bandwidth limit, which leaves a hard shelf in the spectrum. Finding that shelf tells you what a file really is, regardless of what the tag claims — which is how you catch a 128 kbps rip re-saved as 320. Loudness is measured to ITU‑R BS.1770, the same scale streaming services use, so you can spot the track that will jump in volume mid‑set.