[Algorithms] Logarithmic Volume vs. Linear Voltage ?

[Michael P. <MPo...@cy...>]

Is there a formula to convert a logarithmic volume to/from a linear
voltage?  The PS2 uses a linear voltage, but DirectX uses a logarithmic
volume.  I'm trying to match the two up. i.e. Our engine accepts a
percentage volume; how do I convert this volume to it's "native" value
for each platform?

One of the posts in the PS2 SPU newsgroup mentioned doubling the voltage
gives a +6 dB increase, but I don't see where this values comes from.

We now return you to our regularly scheduled debate on floating-point
precision and epsilons...:-)  Lots of good info in that thread!