How to Convert M4A to MP3 on a MacOS

If you are trying to convert an audio recording made with QuickTime or any other m4a files to MP3s or AACs on a Mac, you can do it using iTunes. Here is how.

Convert m4a to mp3

1. Launch iTunes on your Mac.
2. Go to iTunes Preferences and click on the General
3. Now, click on the Import Settings button.
4. Set “Import Using” to MP3 Encoder.
5. In the next drop-down choose the bitrate for your mp3s. (Select Custom if you want to specify more options).
   
6. Click OK and OK again, to close Preferences.
7. Now, go to the Music list (click the music icon in the top left corner of iTunes).
8. Select the files you want to convert. If the files are not present in iTunes library, drag-and-drop them into iTunes and then select them.
9. Click the File menu, navigate to “Create New Version” and choose “Create MP3 version.” (In iTunes 11 or earlier versions, choose “Create MP3 version” from the Advanced menu.) You can also right-click the file you want to convert and choose Create MP3 Version from the menu.
   
10. Once you click “Create MP3 version,” a new (mp3) version of the song(s) will be placed in the music list while the original versions will also remain there.
11. To save the new mp3s elsewhere, just drag them out from iTunes (this will not remove them from iTunes Library). You can delete any files as required in the Music List. (do not tamper with the actual library in the Finder).

Convert m4a to aac

1. Launch iTunes.
2. Go to iTunes Preferences and click on the General tab.
3. Now, click on the Import Settings
4. Set “Import Using” to AAC Encoder (this may be the default choice).
5. In the next drop-down choose the bitrate for your aac files. (Select Custom if you want to specify more options).
6. Click OK and OK again, to quit Preferences.
7. Now, go to the Music list (click the music icon in the top left corner of iTunes).
8. Select the files you want to convert. (If the files are not present in iTunes library, drag-and-drop them into iTunes.)
9. Now, click the File menu, navigate to “Create New Version” and choose “Create AAC version.” (In iTunes 11 or earlier versions, choose “Create AAC version” from the Advanced menu.) You can also right-click the file you want to convert and choose Create AAC Version from the menu.
   
10. Clicking on “Create AAC version,” will create duplicate AAC versions of your songs. Now you can delete the original versions of your songs in iTunes.
11. To save the new aac files elsewhere, drag them out from iTunes (this will not remove them from iTunes Library). You can delete any files (including the aac files) as required in the Music List. (do not tamper with the actual library in the Finder).

Note:

Converting files to mp3s or aac (using the proper compression) works by leaving out bits of the original sound. It is assumed that these changes cannot be noted because they are masked by other sounds.

However, converting mp3 or aac files to an uncompressed format (such as WAV) cannot restore those missing sounds. So, if you ever convert mp3s to wav audio files, keep in mind that you are maintaining the same quality and just making the files a lot bigger.