Convert mp3 to m4r

1. What's the M4R file?
iPhone ringtones' format are slightly different than other ringtones' format. First of all the format is based on MPEG-4 but renamed to have an M4R extension (R for ringtone) and secondly the sound spectrum is quite different from other mobile phones.

The existence of different file extensions for naming audio-only MP4 files has been a source of confusion among users and multimedia playback software. Since MPEG-4 Part 14 is a container format, MPEG-4 files may contain any number of audio, video, and even subtitle streams, making it impossible to determine the type of streams in an MPEG-4 file based on its filename extension alone. In response, Apple Inc. started using and popularizing the .m4a file extension. Software capable of audio/video playback should recognize files with either .m4a or .mp4 file extensions, as would be expected, as there are no file format differences between the two. Most software capable of creating MPEG-4 audio will allow the user to choose the filename extension of the created MPEG-4 files. The same is true for .m4r which essentially is the same as an .m4a file but with a different extension. The dedicated extension ensures that when an .m4r file is dragged to iTunes for example - the ringtone is automatically recognized and installed - ready to be synced with the iPhone.

2. How to convert mp3 to m4r?
a. Download iPhone Mobile Ringtone Converter from http://www.ringtone4me.com
b. Install and run iPhone Mobile Ringtone Converter, it will display following main window,

c. You can click Settings - Option to select m4r format as exporting ringtone format. Click 'OK' to close it.

If you want to convert mp3 to other ringtone format, like as mmf, or amr/awb, you can also select it.

d. Click button 'Open File' to import audio/video file into file list-box, please refer to following image.
e. You can play the media file first, then drag the start time triangle and end time triangle to select ringtone part.
f. Click button 'Create ringtone Now!' to create the ringtone file, the default output folder is in My documents\iPhone ringtone\.

Note:
1. You can adjust the percent of audio fade in/out within the whole audio/video file.
2. You can click the button 'Select Output Folder' to export ringtone to another folder.