Compare Audio Files

How it works

1. Choose file A and file B.
2. Read the properties and loudness side by side.
3. Play and switch between A and B at the same position.

What you get

Add a file as A and another as B. The page measures both and shows their properties side by side: format, codec, bitrate, sample rate, bit depth, channels, duration, size, loudness, loudness range, true peak, sample peak, RMS, dynamic range and the estimated bandwidth. Rows that differ are highlighted and say by how much. Both waveforms are drawn one above the other.

It suits questions like "what did the encoder change?", "is the remaster louder?" and "did exporting alter the file?".

Listening: A/B switching

Both files play on the same audio clock at the same moment and the A and B buttons only change which one you hear, so the switch is instant and always at the same position. The A and B keys do the same, and Space plays and pauses. "Match loudness" lowers the louder file to the level of the quieter one, because people tend to prefer the louder version even when it is not better.

If the page finds that B is shifted against A (common after encoding, because encoders add a short delay), "Line up B with A" starts B at the matching point. Playback covers the first 10 minutes of each file.

Null test

The null test lines B up with A within one second, subtracts it and measures what is left over the first minute. A silent result means the files are identical. A result far below the original (more than 60 dB) is inaudible, and a smaller one shows how much a lossy encode changed the sound. It only means something when both files come from the same recording at the same level: a different volume or mastering shows up as a large difference even when both sound fine, and it is skipped when the sample rates differ.

Questions