Why does Aauto clip music faster for only a few seconds?

1. Open iTunes and find the music:

1. Cut out a complete piece of music, right-click the song-select Show Introduction:

3.option- Adjust the start and end time to keep it within 40 seconds (inclusive):

4. Successfully created, the new ringtone will be at 0:35 seconds:

5. Right-click the new ringtone-Create AAC version-Create successfully:

6. After successful creation-continue to right click-display in Windows Explorer:

7. Change the format to XXX. M4r- There may be an error after the change-Continue to change:

8. Then open the iTunes database-select ringtone-synchronize ringtone-synchronize-finish:

9. There will be a ringtone in your mobile phone in one minute. Find by:

Settings-sound-mobile phone sound-your own ringtone.