Have you noticed how tense your jaw is? I'm willing to bet the source of the problem is all in your head, literally. Your facial muscles are clenched. Relax your jaw.
And druel on the keyboard?
Had a friend in the youth who did that from time to time. Not nice looking.
But I understand what you mean. I sometimes also bite my teeth together but I usually discover that. But even though I do not change face a lot, it do not think this is my problem. I just see very few reasons to move around my head or change face.
Your neck is very tense. Try stretching your anterior deltoids and strengthening your posterior deltoids.
I guess that is from scale as it is not possible to see in the other videos? When I must do something that is technically demanding as this 2-hand 4 octave chromatic scale, I tend to become tensed in my entire body. But if I try to relax, I immediately play wrong. Is not this the case for you? Can you play something in full speed relaxed? Creating the focus is how I raise the speed the extra 20% but I cannot keep it for very long. Just a few seconds.
How about your eardrums? It is very easy to almost subconsciously contract the tiny bits that make up and surround the ears.
I don't follow here. How can you control your eardrums?
The muscles on the tops and outsides of your forearms are overactive. Using those long flexors make for very tight wrists.
Arn't you supposed to use these muscles rather than just playing with your fingers (which I have always heard is wrong)?
From the fingers' point of view...I think I'm seeing a lack of transfer of leverage (therefore a lack of legato, maybe?). With each note, it seems that your fingers are trying to initiate a new direction of motion, instead of carrying the mass of your arm smoothly across the keys. (I know from your recordings, you know how to attain this smoothness, you've just acquired some mal-adaptive coordinations. You can break those habits.) Let the keys push your fingers up, instead of lifting them individually. I think you might be activating opposing sets of muscles simultaneously. This creates enormous friction. (Do your forearms get hot to the touch after playing, this is a sign of friction.)
Here, I really think you have a point. I lift one finger while pushing next finger down simultaneously instead of just moving the wrist in the aquired direction and let the key mechanics lift the finger. Is this what you mean?
Tension may also be caused by relying on the pedal to create legato, instead of actually making sure that two fingers are always in contact with the keys to play the legato smoothly.
The timing of the keystroke and the actual sounding of the tone differs significantly between an acoustic and a digital piano. This makes a huge difference in the fine tuning (pun intended) of your playing mechanism. Stop playing on the digital piano!!! I've screwed up my technique more than once on those diabolical gadgets.
That's just some random ideas...
Well, when it comes to digital versus acustic piano, you cannot jus easily say that this differs significantly as it really depends on the instrument. I actually gain more pain from my Schimmel than my digital while my Nylund feels better. Also, several new digital models just rip out the mechanics of the acoustics and digitalize the sound so the action is the same. For example Yamaha GT2 which has the same keys and mechanics as their concert grand and then they use optic sensors to read the key action, converts it to midi and play it back using samples. But with cheap digitals, yes. You need to spend $4,000 or more on a digital to get a good one.
But I went to the local piano shop and played on a Yamaha piano of the silent serie today and this was not bad at all. Here you get a real piano which can be converted to digital and played at in head phones when the family is sleeping. But not cheap at all
. About $8,000. Silent grands cost about $25,000.