rogerch Hey WieWaldi I would be surprised if the action on a well-maintained upright limited the playing of trills or tremolos more than a grand or digital action.
I would be surprised, if the action would not limit it.
Let me be more precise: Both the action and the player's ability limits the repetition speed.
The best analogy is a racing track, and there are two drivers: An average one like you and me, and a fast one like Louis Hamilton. And we have two cars, a Porsche 911 and a Honda HR-V. Needless to say, Louis in the Porsche will race the track the fastest. And needless to say, Louis in the Honda is faster than you and me in the Honda.
But it would be plain wrong to say, we are the only limiting factor in the Honda. I bet, if the racetrack has a lot of long straights and not too many curves, you and me in a Porsche would outrun Louis in the Honda.
With piano actions, it is maybe not that obvious. But it is a difference, if you need to lift the key entirely before you can re-trigger a new note (unmuted), or if the action allows you to repress the key halfway. Any bet, on a computer keyboard you will have the fastest key repetition speed - faster than on both your pianos. Why? Very short key travel, ultrafast key-return because of springs. If I had to rank typical key repetition speeds from fastest to slowest, I would go:
- Computer keyboard
- Spring loaded synth action
- Digital piano / grand piano
- Upright
I put digitals and grands in the same rank, therefore I am not surprised that you reach about the same speed with your Steinway and your ES920. Uprights should be slower, even if one is able to find a very fast upright that beats a very slow digital. But then we are talking about extreme cases and not about what is typical.
Peter Bence used two hands for his record, I am sure he didn't press the key entirely down. He stopped a bit before, let the inertia do the rest, and made use of the bounce back to have a faster key return. The stronger he pushes the key, the faster the bounce back; therefore two hands.
Sorry for the long text, but I am not yet finished. Besides the pure repetition speed, there is a 2nd factor that makes trilling comfortable or not:
Does the action allow to re-trigger the key when it is half way pressed? If yes, it is good, because then the dampers don't mute the tone. This means, you can achieve a nice sounding trill (or tremolo) without the use of the pedal. Typically, grands allow this because they feature double escapement, as well as digitals with 3 sensors as your ES920. Typical uprights (there might be exceptions) on the other hand, mute each note between two strikes.
In Peter Bence's record, you can see the damper is constantly lifted a bit, and you can see, he didn't use the pedal for this. And you can hear, the resonance was not interrupted, not for the tiniest fraction of a second.
