NT multimedia volume control

[Mike Ricos]

Greetings. I have an signal generator and oscilloscope program for winNT
limping along using the standard multimedia API. Now I would like to
control of the volume and line level input sensitivity from my program
(vc++). It is my understanding that only the sound card's mixer utility
can access the volume and input controls via the sound card's driver
(TurtleBeach's technical support can't tell me).  Is this true? Could
any of this info be tucked away in the registry somewhere? Is there any
hope of mapping a .wav file's digital amplitude to a real world voltage
value?

On a related note, Microsoft's _Inside DirectX 5.2_, p 213, suggests
that you may be able to control some sound card's volume control via
DirectX but the book is ambiguous on this point. Can anyone shed light
on how directX implements volume control? More specifically, is it
possible to control .wav file output using the soundcard's hardware
while overriding the global mixer application?

Thanks, I will summarize responses and post my findings.

Mike
--
miker at comm.mot.com