Open two takes or two mixes, play them together and flip between A and B at the same second, at matched loudness so the louder one doesn’t win just for being louder. Free, no sign-up, and your audio never leaves your device.
Open version A and version B, press play and switch between them: the other version picks up at the same second, so you only hear what changed. The tool matches their loudness with an approximate LUFS reading, so the louder file doesn’t sound better just for being louder, and lets you shift B until both line up.
The two things that ruin a comparison
The louder version almost always sounds better, even when it’s only a decibel louder, and every time you switch files by hand you lose your place and end up comparing your memory of the other one. Here both versions play at once in the background: switching only changes which one you hear, at the same moment, and the louder one is turned down to the level of the quieter one.
Open two versions
AVersion A
BVersion B
MP3, WAV, M4A, OGG or FLAC, up to 10 minutes each. They stay on your device.
A
B
0:000:00
Space: play or pause · A and B: switch version · X: flip · ← →: 5 seconds
Measuring loudness…
Loop a section
No loop yet.
Set the start and the end while it plays, then flip between A and B inside the loop.
Notes
Your files stay on your device: nothing is uploaded and you need no account. Close the tab and they’re gone.
How to compare two takes or mixes
1Open version A and version B: two takes of the same song, two mixes, or your mix next to a reference track.
2Press play and switch with the A and B buttons (or the A and B keys). Leave “Match loudness” on so you judge the sound, not the volume.
3If one version starts earlier, move B a few milliseconds at a time until a drum hit or the first word lands together in both.
4Loop the part that matters, like the chorus, and flip back and forth. Add a note at the second where something changes.
5Copy your notes for whoever is mixing, and name the winner clearly so it doesn’t end up as “Mix_v23_FINAL_final”.
Frequently asked questions
Are my audio files uploaded anywhere?
No. Both files are decoded and played inside this browser tab, on your device. Nothing is sent to Zoundroom or anyone else, nothing is saved, and closing the tab clears them.
Why should I match loudness when comparing mixes?
Because we hear the louder version as better: more bass, more detail, more punch, even when the difference is one decibel. The tool measures each file’s integrated loudness and turns the louder one down so both play at the same level. It never boosts the quieter one, so nothing clips. Turn it off when the level itself is what you’re checking.
How accurate is the LUFS reading?
It follows the ITU-R BS.1770 method (K-weighting and gating) over the whole file and reads the EBU test tones within 0.1 LU, but it isn’t a certified meter and it doesn’t measure true peak. Use it to compare fairly, not to sign off a master for a streaming spec.
What if the two versions don’t start at the same time?
Move B with the “Line up B” control, up to 10 seconds either way in steps as small as 1 millisecond. Pick a sharp sound, like a snare hit or the first consonant of the vocal, and shift B until it lands together with A; the two waveforms show it. If B is shorter, it goes silent when it ends.
Can I compare my mix with a commercial reference track?
Yes: open your mix as A and the reference as B, keep loudness matching on and loop the same section of both. Finished masters are usually much louder than a mix in progress, which is exactly why matching matters.
Does it work on iPhone and Android?
Yes, in Safari on iPhone, Chrome on Android and any current desktop browser. On an iPhone, tap play to start the sound; on older iOS versions, turn off silent mode if you hear nothing. Each file can be up to 10 minutes long, and a long WAV can take a few seconds to open on a phone.
Get started in 4 steps
Picked the take? Keep it with the song
Create your account
Open Zoundroom in your browser or download the app from the App Store and Google Play.
Create your first project
Create the safe space where your music lives and grows.
Import your ideas
Keep your recordings, lyrics, notes, and files in one place.
Collaborate and share
Invite other artists and collaborate in real time, each from their own device.
