To keep Audacity labels aligned, make the audio and label timing change together. Audacity 4 uses explicit editing variants; Audacity 3 uses sync-lock. After each cut or insertion, check a later label against its original sound.

This guide covers one task: shortening or extending a labeled audio sequence on a Mac while keeping its markers useful. The examples use illustrative synthetic tones and timestamps, rather than recorded material.

Which editing workflow matches your Audacity version?

Audacity’s current Mac download is version 4.0.1. Audacity 4 removed sync-lock and introduced explicit cut, delete and paste variants for controlling whether later material moves. Older instructions telling you to enable sync-lock therefore apply to the 3.x workflow, not the current interface. Download Audacity for macOS, Audacity 4.0.0 Release Notes

Choose the relevant path before editing:

Your task Audacity 4 Audacity 3.x
Remove time and bring later material forward Use an explicit close-gap command with the appropriate scope Enable sync-lock for the audio and label group, then cut or delete
Insert audio and move later material back Use the paste variant that preserves synchronization on all tracks Enable sync-lock, then paste at a cursor position
Remove sound while preserving existing timestamps Use silence or an explicitly chosen leave-gap operation Use silence or a leave-gap operation
Correct labels already displaced Inspect and edit label times Undo the edit or correct label times; enabling sync-lock does not repair earlier offsets

The command distinctions come from the current Edit menu documentation and Mac keyboard shortcut reference, together with the older sync-lock documentation.

What exactly needs to stay aligned?

A label track holds annotations rather than audio. A point label marks one instant; a region label marks a span with a start and end. In Audacity’s standard label text format, a point has identical start and end values. A region has different values. Label Tracks, Importing and Exporting Labels

For example, imagine a synthetic sequence with a point label named Tone B at 10 seconds and a region named Tone C spanning 14–18 seconds. If you remove two seconds before both sounds and close the gap, their correct new times are 8 seconds and 12–16 seconds. If you insert three seconds before them, their correct times become 13 seconds and 17–21 seconds.

These are calculated expectations, not measured application results. They give you a precise check: alignment means that the label still identifies the same sound, even though its timestamp changes.

An edit inside a labeled region needs closer inspection. Its start and end may require different adjustments, and a label describing fully removed audio may no longer be useful. Checking only a distant point label cannot establish that every region boundary is correct.

How do you cut audio in Audacity 4 without losing alignment?

First save a separate working copy using File > Save as. The current manual documents this as creating a separately saved project copy. That gives you an unchanged reference for comparing label times. File menu

Remove a duration and close the gap

  1. Stop playback and select the exact time range in the waveform, rather than selecting characters in a label name.
  2. Decide whether the change should affect the whole project’s later timing.
  3. For a project-wide change, use Delete and close gap (all tracks). Its documented Mac shortcut is ⌘ + Backspace or ⌘ + Del.
  4. Inspect a point label after the edit and both boundaries of any region touching it.
  5. If label timing does not match the intended result, undo before making further edits, then use the correction method below.

Audacity also provides Delete and close gap (per track), using Shift + Backspace or Shift + Del. That narrower scope matters when several tracks must remain aligned. The explicit variants avoid relying on the remembered behavior of ordinary deletion. Keyboard Shortcuts

For a cut that puts material on the clipboard, Audacity’s first-use behavior dialog offers leaving the gap or closing it, with different ripple scopes. The chosen behavior is remembered and can be changed in Audio editing preferences. Check that scope before using ordinary Cut repeatedly. Edit menu

The current documentation describes these commands primarily through their effects on audio and clips. Treat a label-time check as part of completing the edit, especially where a region crosses the cut; do not assume the command name resolves every label boundary.

Keep the timeline length unchanged

If the objective is to remove a synthetic tone while preserving every later timestamp, select that tone and use Silence, whose Mac shortcut is ⌘ + L. Silencing replaces the selected audio without changing its length. Later material consequently keeps its position. Tools toolbar, Keyboard Shortcuts

A label within the silenced interval may still need renaming or removal because its sound has changed. Its timestamp being unchanged does not establish that its description remains useful.

How do you insert audio in Audacity 4?

Copy the synthetic audio you want to insert, then click a single insertion position in the destination waveform. Using a cursor position makes the intended duration change unambiguous for this workflow.

Use Paste (preserves synchronization on all tracks), documented on Mac as ⌘ + Option + Shift + V. Other variants include Paste (pushes clips on selected track) and Paste (overlaps other clips), so the paste choice is consequential. Keyboard Shortcuts

For the illustrative three-second insertion before Tone B, inspect whether that point now identifies its sound at 13 seconds and whether Tone C spans 17–21 seconds. Inspect labels crossing the insertion separately. If their times need correction, the label editor provides a supported way to enter exact boundaries.

A project-wide paste variant has a broader scope than a single-track insertion. Use it when the later project material should move together; otherwise, decide which audio and labels should retain their original timing before proceeding.

How does the Audacity 3.x sync-lock workflow differ?

In the older workflow, arrange the related audio tracks together, followed by their label track, and enable Tracks > Sync-Lock Tracks. Select an audio track and look for the sync-lock indicators on the intended tracks. Grouping follows track order: a label track can terminate a group, and several label tracks can belong together at its bottom. Sync-Locked Track Groups

With the intended group active, ordinary Cut or Delete removes time across that group. Pasting at a cursor inserts audio into the selected destination and inserts silence in other affected audio tracks to maintain synchronization. The manual’s labeled example shows a removed label disappearing while a later label moves with the remaining audio. Sync-Locked Track Groups — Editing

Sync-lock is off by default, and its setting applies across projects until changed. It preserves existing alignment during subsequent edits; switching it on after a mistake does not realign displaced labels. Sync-Locked Track Groups

For a deletion without sync-lock, the older manual supports selecting the same interval in both the audio and label tracks before deleting. Do not generalize that deletion method into an assumption that every insertion behaves identically. Label Tracks

How can you check and repair an offset precisely?

In Audacity 4, open Show label editor from the label track’s menu. Its table exposes each label’s text, start and end times for direct editing. You can also move a label by dragging its name tag or resize a region by dragging an end. Use numeric editing when you know the exact offset. Label Track Item

Use this calculation as a diagnostic for labels entirely after an edit:

Illustrative operation before the label Required adjustment Point originally at 10 seconds Region originally at 14–18 seconds
Delete 2 seconds and close the gap Subtract 2 seconds 8 seconds 12–16 seconds
Insert 3 seconds Add 3 seconds 13 seconds 17–21 seconds
Silence 2 seconds without moving audio No timing adjustment 10 seconds 14–18 seconds

Apply a correction only if it has not already happened automatically. For a point, retain equal start and end values. For a region wholly after the edit, change both boundaries by the same amount. When a region crosses the edit, inspect its surviving sound and set the boundaries individually.

After several edits, a single global offset may be wrong: different labels may follow different numbers of insertions or deletions. Compare one label before the first change, one immediately after each changed interval, and the final region’s endpoint. This local check helps identify where timing first diverged.

What should you save or export after editing?

Save the editable project, then export the finished audio and any required label text separately. Audacity distinguishes saving the project from rendering an audio file; an audio export does not preserve the editable track structure. Export Menu

In Audacity 4, open the desired label track’s menu and choose Export labels to export that track’s labels. The current manual explicitly documents this track-specific behavior. Label Track Item

Older export instructions differ: the legacy File > Export Other > Export Labels command combines multiple label tracks into one text export and cannot export only a selected portion. Its standard text format contains tab-separated start time, end time and label text. Keep those older limitations distinct from the current track-menu behavior. Importing and Exporting Labels

Export labels after finishing the timeline edits so the text records the final positions. Before closing the project, play the synthetic sounds at a later point label and across a region boundary, then confirm their numeric times. That final check connects the chosen editing command, the visible labels and the timing you actually need.

Sources