Windows 7: How to change volume level audio >scale< in windows?

Well I have a nice subwoofer in my room with 14 speakers and when I always need to turn down the volume on my laptop to 1, or even near 0 (so 1% on the windows volume control options and 1% on the windows media player, which makes effectively 0.01% total volume).
I have to do this because when the volume is higher than 3-4% it is getting really loud in my room.
Now I always have problems because I use my laptops media buttons to make the volume higher/lower, and those buttons increase/decrease the windows volume by 1%, this is way too much.
I would like to increase/decrease the windows volume by 0.1% with each media key hit.
Is this possible?
Or is it possible to change the windows scale from 0...100 to 0...10000 ?
(making 10000 the same sound level as 100, and 5000 the same as 50)?
And no I can't change the sound level of my subwoofer, it's broken and I can only control the bass level.