After this process is complete, you will see an additional song in the library below the original post. This is the piece of music you chose to cut out above.
Tip: After successfully performing this step, you can re-enter the original track, reset playback time and stop time so that the song can be played completely once you want to listen again.
Right-click on the cut music, select Show in Finder to open the folder containing the file. Select the file with the width section m4a.
Proceed to change the m4a extension to m4r . A notification window will be displayed, continue to select Use m4r.
Return to iTunes again, right-click the ACC version created in step 3 and click delete from the library (You should choose Keep files ).
Connect your device to iTunes, select the Sync Ringtones section to add a ringtone to your phone. Then, work on the iPhone to select the ringtone you just created.