This API is intended to be used to play sound effects or to make the device vibrate. You use SystemSound.PlaySystemSound to play short sounds and SystemSound.PlayAlertSound to play either the sound or vibrate (depending on the device settings).

Unlike the AVFoundation.AVAudioPlayer which works with the audio session and is able to dim your audio, play in the background and interact with the system based on a set of rules, the SystemSound does not support this. So you should in general avoid using it for anything but sound effects and device vibration.

As of iOS 8, SystemSound has the following restrictions:

• Audio Format: PCM or IMA4 (IMA/ADPCM).
• Audio Container: .caf, .aif or .wav containers.
• At most 30 seconds of duration.
• There is no volume control, this uses the system volume.
• Sound plays immediately.
• Only one sound can be played at a time, there is no way to play more than one sound at a time.

To play a sound, you first create an instance of the SystemSound object, either via the constructor, or one of the SystemSound.FromFile methods. Once this object has been created, you call one of the playback methods SystemSound.PlaySystemSound to play short sounds and SystemSound.PlayAlertSound.