Many iTunes music songs may have the .m4a extension. However iPhone only accepts .m4r as its ringtones. Is there any way to convert .m4a to .m4r so I can use it as ringtones on iPhone?
Well in fact, both .m4a and .m4r audio files are encoded with AAC codec. M4A audio files can be used as iPhone ringtones without conversion. You can simply rename the file and change its file extension from .m4a to .m4r. To rename file or change file extension on Windows, right click the file in File Explorer, choose Rename from the context menu, then type in new file extension. If you are on Mac, you can follow this guide to change file extension on Mac.
Then add the .m4r file(s) back into iTunes, iTunes will recognize them as ringtone files. Your ringtones are now ready to be synced to iPhone through iTunes.
Trim music & audios in iTunes
A ringtone should be less than 40 seconds.If the audio or song is very long, you can use iTunes to cut of unwanted parts. In an earlier article, we showed you how to create ringtones for iPhone using iTunes. You will learn how to convert all kinds of music to ringtone format and split long audios using iTunes from this linked guide.