Carlos, My best advice is to keep it simple.

Okay, why does windows have some control over the digital files ? It does for the same reason a Cd walkman or portable mp3 player have control over the volume and tone controls . Computers were not intended to be connected to an amplifier any more than a walkman was, therefore the consumer needs a way to adjust the volume and tone. My point here is the "why" of it matters little because it designed function cannot be changed. How you deal with it right now does.

I don't think you need a sound engineer to keep windows influence to minimum, simply keep the EQ off , if you use windows media player. Keep the volume of the computer on max. This is how I listen to my music and it sounds excellent. I use both speakers and headphones.

Enjoy the music