Evaluating piano keyboard actions

[phatmann]

In the "MP8 and Nord Stage" thread, there is an interesting discussion about digital piano keyboard actions. As has been said many times, this is a very subjective area. There is no one action everyone likes. However, I propose that there are indeed particular qualities of an action that can be assessed more readily than the action as a whole:

 

* Speed. This is a measure of how fast notes can be played. One possible metric is how many times a single note can be activated per second.

 

* Expressiveness. This is a measure of the dynamic range the action provides when played by competent pianist.

 

* Depth. This is a measure of how the action feels when played hard. The length of the key travel and the feel when the key "lands" are the two main factors.

 

Each of these factors could receive a rating from 1-10. A good grand piano would receive a 10 in each category, so it becomes the standard on which to judge.

 

Another interesting discussion in the MP8 thread was whether simulating a piano action in a digital keyboard was a good idea, since you can only come close, and for some it's not close enough. Using the categories above, the question can be rephrased: can an action be built that scores very high in speed, expressiveness, and depth, but yet does not feel like a grand piano? I don't have an answer today, but it's an intriguing question. Keyboards that use fluids instead of hammers/weights/springs (e.g. PX-310) might be one promising area.

 

Below, I rate a few digital pianos based on the above categories. Of course, these are still subjective, but I wanted to see what folks thought of this process. I am not really comfortable with the scale yet.

 

What I would really like to do is find a place where other folks can submit these numbers, so we could start collecting averages. When you cannot find the keyboard in the stores, this data might be helpful. If anyone knows of a good place where such data could be collected, let me know. I might be willing to build it myself if I have to.

 

Keyboard: Speed, Expressiveness, Depth

Steinway grand:       10  10  10
Casio PX-310:          6   7   9
Roland 700SX:          8   7   7
Roland 300SX:          7   6   2
Yamaha P90:            7   7   7
M-Audio ProKeys 88:    7   5   4 

[Garrafon]

But, going back to the age old problem, aren't certain of your factors (expressiveness and maybe depth) subjective? Although you may say depth is objective, is short depth or long depth preferable? Won't opinions vary?

 

Plus, expressiveness is somewhat adjustable within any particular digital piano.

 

I like your thought process of trying to turn this perpetual discussion into a scientific one, I'm just not so sure its doable. Hey, some love a Steinway and some prefer to play other brands. To each his/her own.

[phatmann]

Perhaps we can make each factor more quantitative. For example, speed could be "max notes per second". Part of depth could be "key travel length", but we still need some way to characterize the "landing"; I welcome suggestions. For expressiveness, one could measure the MIDI velocity range for a few standard tunes when played by a decent pianist.

 

This said, there is always going to be subjectiveness to this. I am just seeing what we can do to have more focused subjectiveness :-)