It’s easy…
- Make a short MP3 file by ’snipping’ out the section that you want to use as your ringtone. I use an old copy of TotalRecorder
- Convert the short MP3 to to AAC. You can do this in iTunes if you set your Preferences | General | Import Settings to AAC Encoder, add the short MP3 to your iTunes library, and then right-click on the MP3 and select Convert to AAC
- Use Get Info to find the .m4a file that iTunes creates (it puts them in silly places) and change the extension from .m4a to .m4r
- Copy the .m4r file into /Library/Ringtones on your iPhone using ssh/scp.
- If it’s not loud enough, you can use mpTrim to pump up the volume of the MP3 a bit and then re-encode, etc…
I found these basic instructions very helpful in figuring this out.
Using iTunes to convert to AAC is a bit of a pain — does anyone know of a good standalone MP3->AAC converter?
Update: notes here on how to do custom SMS tones and such…



