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How to play or convert an AMR voice recording on a Mac

· 6 min read

An AMR file is a speech recording made with a codec designed for phone calls. It turns up from older phones, some voice recorder apps on phones, call recording features and voice messages exported from messaging apps. On a Mac it may not open in the apps you would expect, and the reliable fix is to convert it once to M4A, MP3 or WAV, which every app on your Mac handles.

Converting does not make it sound better. It makes it playable, shareable and editable.

What AMR actually is

AMR stands for Adaptive Multi-Rate. It was built to squeeze a human voice into very little data so it could travel over a mobile network, and it is very good at that job. There are two common variants:

  • AMR-NB (narrowband): telephone quality, sampled at 8 kHz. These are the classic .amr files, and they are tiny.
  • AMR-WB (wideband): noticeably clearer speech, sampled at 16 kHz. These sometimes use the .awb extension, and sometimes still use .amr.

Both throw away everything outside the range of human speech. Music recorded as AMR sounds thin and watery, and no conversion will bring back what was discarded.

You can check which kind you have. Open Terminal and run:

head -c 9 ~/Downloads/recording.amr

A narrowband file shows the letters AMR within the first few characters, and a wideband file shows AMR-WB. If you see neither, the file may be something else with an .amr name, or AMR audio inside a different container such as 3GP.

Try the built-in apps first

Support for AMR in Apple’s own apps has varied between macOS versions, so the honest advice is to try before converting.

  1. Select the file in the Finder and press Space. If Quick Look plays it, the Mac can decode it.
  2. Right-click the file and choose Open With > QuickTime Player.
  3. If QuickTime opens it, choose File > Export As > Audio Only. That saves an M4A copy you can use anywhere.

If neither Quick Look nor QuickTime plays the file, macOS on your Mac does not decode that recording, and you need a converter that does.

Which format to convert to

Pick the target by what you are going to do with the recording, not by habit.

  • M4A is the natural choice for keeping recordings on a Mac or iPhone, sending them in Messages or dropping them into a notes app. It is compact and plays everywhere Apple.
  • MP3 is the safest choice when you are sending the file to someone on an unknown device, uploading it to a website, or attaching it to a form. Almost everything accepts MP3.
  • WAV is uncompressed. Use it if the recording is going into an audio editor, a transcription service that asks for WAV, or evidence handling where you want to avoid another round of lossy compression. It will be many times the size of the AMR file, with no audible improvement.

Whichever you choose, there is no benefit to picking a high bitrate for the output. The source is telephone-band speech; a modest MP3 or M4A setting captures all of it.

Converting AMR on a Mac with Manatee

Manatee reads AMR among its 122 accepted input types and converts to MP3, M4A, WAV or FLAC, among other targets.

  1. Drag the AMR file, or a whole batch of them, onto the Manatee icon in the menu bar or into its window.
  2. Choose Convert and pick MP3, M4A or WAV.
  3. The converted copies appear next to the originals. The AMR files are left exactly as they were.

You can also right-click files in the Finder and choose Services > Fix with Manatee to start from there. The conversion runs on your Mac with the audio engine bundled inside the app, so nothing is uploaded. For voice recordings that matters: call recordings and voice notes are often personal, and an online converter means handing them to a server you know nothing about. Online file converters: what you give up goes into that trade in more detail.

Manatee is free for 24 hours with every feature, which is plenty for clearing a folder of old recordings, and $9 once after that.

AMR inside old phone videos

Videos from older phones often come as .3gp files, and the audio track inside is very often AMR. That is one reason those clips play silently or not at all on a Mac. Converting the whole video to MP4 turns the AMR audio into AAC along the way. How to convert 3GP phone videos to MP4 covers that case. If you only want the sound from one of those clips, convert it straight to M4A or MP3 instead.

When the recording will not convert

If a converter reports an error, check the basics before assuming damage.

Is the file complete? A voice message exported or copied while the recording was still in progress can be cut short. A file that is only a few kilobytes for what should be a long call is incomplete. Export it from the source again if you can.

Is it really AMR? If the header check above shows something else, the extension is wrong. Some recorders use .amr loosely. Try the file in Quick Look under a different extension, or run file ~/Downloads/recording.amr in Terminal to see what the Mac thinks it is.

Was it renamed after a transfer? Some messaging apps export voice notes with generic names and no extension at all. Adding .amr helps only if the header matches.

Questions

Can I play AMR files in the Music app? Music imports the formats Core Audio can decode on your version of macOS. If Quick Look will not play the file, Music will not either. Convert it to M4A or MP3 first, then add it.

Will converting AMR to WAV improve the sound? No. WAV stores the audio without further compression, so it avoids adding new loss, but it cannot restore what AMR removed when the recording was made. Lossless vs lossy explains why.

Is AMR good enough for transcription? Speech in AMR is usually clear enough for a person or software to transcribe, since the codec is built to keep voices intelligible. Narrowband recordings of fast or quiet speakers are harder; wideband recordings do better.