a/b lab

Hear the difference, instantly.

Load two versions of the same track: your working mix and the new revision, or a master against its reference. Both run in perfect sync; tap A or B to switch which one you hear, seamlessly, without ever interrupting playback. Loudness matching keeps the comparison honest, and blind mode keeps you honest.

Track A

Insert track A

tap to browse · or drop a file

Track B

Insert track B

tap to browse · or drop a file

tap A or B any time; playback never stops
0:00.0 / 0:00.0
waveform hidden in blind mode

Both tracks decode once and play in lockstep on a shared clock; the A/B switch is a gain crossfade a few milliseconds long, which is click-free but effectively instant, so your ears never lose the moment. Match loudness attenuates the louder file to the quieter one’s RMS, since louder almost always sounds “better.” Blind shuffles the pair behind X and Y so expectation can’t steer the verdict. Tap the waveform to seek. On a keyboard: space play/pause, A/B or arrow keys to switch, S to stop.