Just replied in the other topic about this, but you reminded me that I had the same thought after reading Heinrich Neuhaus. The mass of an object (i.e. your arm) shouln't really make any difference. It is the velocity that it travels. So, YES, if you played two chords together (LH ppp and RH fff) the RH would actually start its descent slightly after the LH.
I experimented with it and believe it is true.
Try this:
- Play two chords (just simple C chord CEGC in each hand) as quietly as possible
- Keep playing them to a regular pulse (say quarter note = 60)
- Now, keep the LH moving with that same feel and rhythm (i.e. v quiet and regular) but now try to play the RH forte. HOWEVER...
- instead of how you normally think ("Hmmm, now I need to play RH loud and heavy" or whatever you think) consciously think the following:
a) I'm going to start the RH slightly after the LH
b) I'm still going to make the two chords must sound at exactly the same time
After a few attempts, I believe your brain can sense that the RH sets off ever so slightly after the LH, EVEN THOUGH they land at the same time. Not only this, but it seems much easier to keep the LH soft while the RH plays loud (simply as a consequence of the speed needed).
Ultimately, I think our brains are much smarter than we imagine and subconsciously, in the end, we don't think "play faster and slight later", we just think "play the RH louder". But I think that the subconscious process IS based on the faster (rather than heavier) approach. And that's why it's hard for us to play that way at first. Because when you think "play heavy", both hands come out heavy.
I think these kinds of conscious focused exercises help. They certainly helped me. I'm interested to know what happens for you when you try this exercise.
Best,
Goose