Creates a voice structure and allocates a voice from the digital sound
The passed frequency, sample format and channel configuration are used
as a hint to what kind of data will be sent to the voice.
However, the underlying sound driver is free to use non-matching
For example it may be the native format of the sound hardware.
If a mixer is attached to the voice, the mixer will convert from the
mixer[aq]s format to the voice format and care does not have to be
taken for this.
However if you access the voice directly, make sure to not rely on the
parameters passed to this function, but instead query the returned voice
for the actual settings.