A:

This is a common source of confusion. Basically, the most important thing to remember is that the maximum distance has nothing to do with the volume falloff curve! Only the minimum distance matters for the falloff curve.

The volume of a sample falls off by half every time the minimum distance is doubled. So, if you set your minimum distance to 3, then this falloff curve is in effect:

Distance: less than or equal to 3 meters. Volume: 100%.
Distance: 6 meters. Volume 50%.
Distance: 12 meters. Volume 25%.
Distance: 24 meters. Volume 12.5%.
Distance: 48 meters. Volume 6.25%.
etc...

So, you can see that the maximum distance doesn't affect the volume falloff curve at all! The maximum distance just sets a hard clip point - the volume is forced to be zero at maximum.

Also note that some DirectSound drivers don't implement the maximum distance correctly with the DSBCAPS_MUTE3DATMAXDISTANCE flag in effect (which Miles uses). At the maximum distance on these drivers, the volume doesn't drop to zero, instead, it just stops falling off.