Any tip to get high speed but low volume?

[mussels_with_nutella]

I have always (and still now) played in a keyboard. Although my new keyboard seems to be a wall piano, with heavy keys and touch sense, I cannot play fast notes without playing them loud. And it is a trouble when you are playing them as accompanigment of the other hand, whether it is the right or left hand.

Can anyone give me a tip, piece of advise or even étude (i'd prefer the other two and I'd practise myself ) to help me getting that technique?
I have not a mediocre level, but i have had my own problem with my Me and Circumstances