You can also use this technique if you need to divide a lengthy audio file into smaller parts, for whatever reasons whatsoever. So, without any further ado, follow the steps outlined below to use iTunes to crop an audio file:
Open your audio file in iTunes by clicking on it. (If you have set another audio app such as VLC, Vox etc. as your default media player, simply right click the file and “Open With -> iTunes”).
Once you have the file selected and in front of you, press “Command + I” or right-click the file and select “Get Info”.
In the Options tab, enable the checkboxes for Start and Stop time. Now enter the time portion of the song that you want to crop. Once done, click Ok.
Now right click on the file and select “Create AAC Version.” This will result in a new audio file being created which is of the exact length you specified in the “Start” and “Stop” boxes. iTunes will play a “ding” sound once the new version has been created.
Note: Do remember to remove the start and stop times on the original file once you’re done, so you can listen to the full song again. And that’s it. Now you have an easy way to crop your audio files. And if you want to use this new cropped file as a ringtone, check out this post.