3.1.5.25.7 XAudSoundDevice_SetVolume
The XAudSoundDevice_SetVolume message sets the master volume level for all sounds played with the sound device.
The flVolume field specifies the volume level with a value within the range of 0.0 and 1.0.
The fields of the XAudSoundDevice_SetVolume are specified in section 2.2.4.24.7.
The common header fields are specified in section 2.2.4.