Merge audio: settings and best results

What does Merge audio do?

Merge audio turns several audio files into one, on your own computer. Join an intro, an interview and an outro into one podcast episode, or lay a voiceover over background music. In the app the tool is called Merge Audio.

There are two ways to merge. Concatenate plays the files one after another, with a smooth crossfade at each join if you want one. Mix plays them together, each with its own start time and volume. Either way, all the files you add become one new file.

01Step 1: Add your audio files in order

Click Tools in the sidebar, open the Audio tab and click Merge Audio in the Cut & join section. You can also type "merge audio" in the search box at the top.

Drop at least two audio files on the queue, or click it to pick them. Merge Audio takes MP3, WAV, FLAC, AAC, OGG, Opus, M4A, AIFF, AIF and WMA files, and you can mix formats. Video files are listed under Not applicable.

The files are joined in queue order, top to bottom. Drag a row by its handle to move it. You can also reorder them in the Merge studio.

123456

1. 1Merge mode
2. 2Output format
3. 3Default crossfade
4. 4Output name
5. 5Arrange in the Merge Studio
6. 6Run merge

03Step 3: Fine-tune in the Merge studio

Click Arrange in the Merge Studio to see every file as a waveform. The studio shows the mode you picked, and you can switch between Concatenate and Mix at the top.

• In Concatenate, each file is a block, as wide as it is long. Drag a block to change the order. Click a join between two blocks to give it its own crossfade with the slider, or set it to 0 for a hard cut. Reset to default puts that join back to the panel’s value. If you reorder the files here, every join goes back to the default.
• In Mix, each file has its own row. Drag a row sideways to choose when it starts, and use its fader to set its volume, from -60 dB to +12 dB. A white line marks where the result ends.

12345

1. 1Concatenate or Mix
2. 2Drag to reorder
3. 3Seam
4. 4Reset to default
5. 5Done

Click Done to go back to the panel. Studio changes last until you close Hangar.

04Step 4: Run, then check the result

Check where the file will go: Default output folder saves it in your workspace’s output folder, in a merge folder with a subfolder for today’s date, such as 10-15. Click Change to pick another folder for this run. Then click Run merge.

When the run ends, each file in the queue shows Merged, and the panel shows the new file with its size and the number of files it was made from. Click View to listen to it, and Open folder to go to it. See Where your files are saved.

1234

1. 1Merged
2. 2All 3 files merged
3. 3Saved to
4. 4Open folder

Every setting, and when to change it

Default crossfade only appears for Concatenate, and Output length only for Mix. Per-join crossfades, start times and volumes are set in the Merge studio.

Merge mode

Play the files one after another, or all at the same time.

• RangeConcatenate, Mix
• DefaultConcatenate

Output format

The format of the new file. AAC is saved as .m4a.

• RangeMP3, AAC, WAV, Opus
• DefaultWAV

Quality

How much detail MP3, AAC and Opus keep. Higher sounds better and makes a larger file. WAV has no quality setting.

• RangeLow, Med, High
• DefaultHigh

Default crossfade

With Concatenate, how long each join fades from one file to the next. 0 joins them with a clean cut.

• Range0 to 5 seconds
• Default0.5 seconds

Output length

With Mix, when the result ends: with the longest file, the first file in the queue, or the shortest file.

• RangeLongest, First, Shortest
• DefaultLongest

Output name

The name of the new file, without the extension.

• RangeAny file name
• Defaultmerged

Join crossfade (studio)

With Concatenate, its own crossfade for one join.

• Range0 up to half the shorter of the two files
• DefaultThe Default crossfade

Start time (studio)

With Mix, when a file starts playing. Drag its row sideways.

• Range0 or later
• Default0

Volume (studio)

With Mix, how loud a file plays in the result.

• Range-60 dB to +12 dB
• Default0 dB

How do I get the best results?

• For spoken segments, keep crossfades short, from 0.3 to 1 second, so no words are lost. Use 0 when one file should start right where the other stops.
• For music, longer crossfades of 2 to 5 seconds sound smoother.
• For a voiceover over music, use Mix and lower the music, often by 10 to 15 dB, so the voice stays clear.
• To edit the result later, keep WAV. To publish it, pick MP3 at High.
• Trim first. Cut silence or mistakes from each file with Trim Audio before you merge.

Why does a result disappoint?

• The files are in the wrong order. They are joined in queue order. Drag the rows, or reorder them in the Merge studio, then run again.
• A crossfade is shorter than I set. A crossfade can be at most half as long as the shorter of the two files it joins, so a very short file limits it.
• My per-join crossfades disappeared. Reordering the files in the Merge studio resets every join to the default. Set them again after you reorder.
• In Mix, one file drowns out the other. Hangar keeps the volumes you set and does not balance them. Lower the louder file’s fader in the Merge studio.
• In Mix, the result cuts off early. Check Output length: First and Shortest stop before the longest file ends.
• The run failed saying it needs at least 2 audio files. Add another file. Merge Audio needs two or more.
• The run failed with a message about the output name. Remove characters a file name cannot hold, such as : ? * or ", from Output name, and don’t end it with a space or a period.

For other errors, see A file failed: what to check.

Limits

• Merge Audio takes audio files only, at least two per run, and makes one file from all of them.
• The result is stereo. Mono files are played on both sides.
• The Default crossfade goes up to 5 seconds. No crossfade can last more than half the shorter of the two files it joins.
• Settings made in the Merge studio last until you close Hangar. They belong to positions in the queue, so check them again after you add, remove or move files.
• Add audio files, not folders.
• Everything runs on your computer. Nothing is uploaded.