Like their 32-bit counterpart, the high 8 bits are the integer portion of the volume and the low 8 bits are the fractional portion of the volume. For example, a volume setting of 0x01000100 would be full volume on both channels, while a setting of 0x01000080 would be full volume on the right channel and half volume on the left channel. A timed sequence of such calls with increasing values for the left volume and decreasing values for the right volume would make the sound pan from left to right. That's right, with volumeCmd you can overdrive the sound level for that loud crunchy sound so many rockers look for. Using QuickTime 2.1 modifiers track allows you to play sounds with complex effects.
Some developers wish to monitor sound output channels for various purposes, such as level metering.
Sound Manager 3.2.1 helps to solve this problem by allowing users to install pre-mixer components. These are components that are installed in the component chain right before the Apple Mixer component. A pre-mixer component sees the converted sound data from the channel it is installed on. Currently, there is no way to install a post-mixer component which would see the mixed result of all sound channels. Well, actually there is, they are called sound output components.