Why you must level-match an A/B comparison
Ask anyone to choose between two identical recordings where one is slightly louder and most will pick the louder one, describing it as fuller, clearer or more exciting. That bias is strong enough to decide most casual comparisons on its own. Level matching removes it.
Why louder sounds better
Human hearing is less sensitive to low and high frequencies at lower volumes. Turn something up and you hear more bass and more air, which reads as a richer sound. The effect is noticeable at differences of around 1 dB, well below what most people would call “a bit louder”.
Peak level is the wrong measure
Two files can peak at the same level and sound very different in loudness: a heavily limited master and a dynamic mix are the classic example. Matching peaks leaves the louder-sounding version louder.
Integrated loudness, measured in LUFS (ITU-R BS.1770), estimates how loud a whole track sounds to a listener. Matching LUFS is the closest automatic stand-in for matching by ear.
Match, then listen again
Loudness matching is a starting point, not a verdict. Two versions at the same LUFS can still differ in how loud a particular part feels: a brighter master may seem louder in the chorus, a denser one in the verses. After auto-matching, listen to the passage you care about and nudge one track by a decibel if it still stands out.
Then forget the numbers and listen for what you came to judge. Once neither version wins just by being louder, the differences that remain are the ones worth discussing.
Trim the playback, not the file
Level matching should change only how loudly each version plays during the comparison. The files themselves stay untouched: no normalising, no re-rendering, no extra processing that could change the sound you are trying to judge.
Doing it in audiotoggle
Open Adjust levels between the two track cards:
- Auto-match measures both files (LUFS) and trims one to meet the other.
- Or trim each track by hand in 1 dB steps, from −12 to +12 dB.
- The trim is a playback gain only; the uploaded files are never re-encoded.
- On Pro the trims are saved, so everyone opening your link hears the matched balance.