# Version compare
Source: https://docs.aden.space/docs/help/make-music/track-version-compare

Instantly A/B two or more versions of a track at the exact same playhead position. Pick versions from a searchable dropdown, then flip between them with zero gap so you can hear mix, master, and small change differences in context.
{/* Generated by `bun docs:publish` from docs/features/track-version-compare.md: edit the spec, not this file. */}

## What it is [#what-it-is]

**Compare** lets you A/B two or more versions of the same track and switch
between them instantly, without the audio ever stopping or jumping position.
It's built for the moment where you have a mix and a master, or two mix passes,
and you want to hear *exactly* what changed at a given spot in the song.

Because every version you pick is loaded and kept in sync behind the scenes,
flipping from A to B is gapless. The playhead stays on the same beat, so the
only thing that changes is the sound. Each version always plays its
**highest-quality file** (a WAV/AIFF/FLAC master is preferred over an MP3), and
the format it's using is shown on the A/B button so you know what you're hearing.

## Using it [#using-it]

There are two ways in:

* **From the versions toolbar**: click **Compare**, tick the versions you want
  (2 to 6, searchable), then click **Compare**.
* **From a version's “…” menu**: pick **Add to A/B compare** on any version to
  drop it straight into the comparison and open the panel. Add more versions the
  same way; the menu shows a check when a version is already in the set.

Then, in the compare panel that opens above the versions:

1. Press **play** and use the **A / B / C…** cards to switch which version
   you're hearing: the switch is instant and keeps the same position, so it's
   easy to judge loudness (LUFS) and mix/master differences.
2. Each version card shows its own **waveform** with a live playhead. Click or
   drag anywhere on a waveform to jump there; every version follows along so
   you're always comparing the same spot (the transport scrubber works too).

### Sharing a comparison [#sharing-a-comparison]

A comparison is a URL. As soon as the panel is open, the address bar carries a
`?compare=` parameter listing the versions you picked. Copy it (or use the
**link** button in the panel header) and whoever opens it lands on the same page
with those exact versions loaded and the panel already open. Works on both your
track page and public share links.

Keyboard shortcuts while the panel is open: **Space** to play/pause, **←/→** or
the number keys **1–6** to switch version, **Esc** to close.

### Comparison aids [#comparison-aids]

Three optional toggles sit in the panel header, and as small icon buttons
right inside every version card (all off by default, so it stays simple until
you want more):

* **Loudness**: turns on a live **LUFS meter** inside each version card, right
  above its waveform: a momentary loudness bar, a rolling **loudness heatmap**
  over time (colored from quiet → very loud), and short-term + integrated LUFS
  numbers. Because all versions are metered simultaneously you can see, not
  just hear, which master is hotter and by how much (streaming targets sit
  around -14 LUFS).
* **Loop**: loops playback so you can A/B the same passage over and over.
* **Blind**: hides the version names and format badges so you judge by ear
  instead of by label, then reveal to see which you picked.