Custom Sound in Push Notifications

Preparing Custom Alert Sounds

For remote notifications in iOS, you can specify a custom sound that iOS plays when it presents a local or remote notification for an application. The sound files must be in the main bundle of the client application.
Custom alert sounds are played by the iOS system-sound facility, so they must be in one of the following audio data formats:

• Linear PCM
• MA4 (IMA/ADPCM)
• µLaw
• aLaw

You can package the audio data in an aiff, wav, or caf file. Then, in Xcode, add the sound file to your project as a nonlocalized resource of the application bundle.
You may use the afconvert tool to convert sounds. For example, to convert the 16-bit linear PCM system sound Submarine.aiff to IMA4 audio in a CAF file, use the following command in the Terminal application:

afconvert /System/Library/Sounds/Submarine.aiff ~/Desktop/sub.caf -d ima4 -f caff -v

You can inspect a sound to determine its data format by opening it in QuickTime Player and choosing Show Movie Inspector from the Movie menu.

Custom sounds must be under 30 seconds when played. If a custom sound is over that limit, the default system sound is played instead.