From Xojo Documentation

Property (As Integer )
aiOSSound.Volume = newIntegerValue
IntegerValue = aiOSSound.Volume

Supported on Mobile (iOS).

Specifies the volume level of the sound. Default = 100.


The value ranges from 0 to 100. A value of 0 mutes the sound and a value of 100 plays the sound at the "normal" volume set in the OS volume settings.

Sample Code

Lower the sound volume:

mySound.Volume = 50