How to compare two audio files in a browser without uploading them

Use this workflow when two audio exports sound close but you need evidence before approving a podcast, voiceover, music cue, sound effect, or converted file.

A simple waveform view is not enough when one file starts a little later, was re-encoded, or has subtle EQ and loudness changes.

Start with duration, peak level, average loudness, and channel count. These metrics catch obvious export mistakes before you spend time listening through the whole file.

If the files have different start padding, use offset alignment before judging similarity. Otherwise a tiny timing shift can make the entire waveform look different.

Open Audio Diff, click Try sample audio, then click Start Compare. MKDiff generates two four-second WAV files locally: the revised recording contains silence from 2 to 2.5 seconds.

Find that interval in the heatmap and changed-moment list, then listen to the original and revised recordings. This gives you a known edit to check before using your own files.

Choose the original recording on the left and the revised recording on the right, up to 50 MB each, then click Start Compare. MP3 and WAV are useful starting points; decoding support for other formats depends on your browser.

If the recordings start at different times, try Auto align and verify the result by listening. The timing control runs from -2 to +2 seconds: a positive modified offset skips the revised opening, while a negative offset delays it on the original timeline.

Review the heatmap and changed moments, listen to both versions, and compare loudness-normalized mode with raw volume. Normalization can hide a gain-only change, so use raw volume when checking export levels.

Export the JSON report for durations, levels, offset, comparison mode and changed time ranges. Export the difference WAV to hear the residual for the currently selected alignment and normalization.

Treat the score as a sampled waveform estimate, not a listening verdict. Timing and phase shifts can lower it even when two recordings sound similar. Loudness, duration, sample rate and channel count also affect the displayed result; the spectral panel is a separate review aid.

For a brief strong difference, listen at that time for a cut, dropout, click or inserted silence. If differences cover the whole recording, first check alignment, loudness and whether one file was re-encoded.

The timeline starts at the original file’s zero and includes the longer ending after applying the offset. Audio missing from either file is compared with silence. Review that ending when one export was trimmed or padded.

Check that both inputs are valid audio files within the 50 MB limit. If your browser cannot decode a format, export a supported WAV or MP3 and try again.

Long recordings can require much more memory than their compressed size suggests. Compare a shorter excerpt when the tab slows down or decoding fails. The file-size limit is not a guarantee that every recording will fit in memory.