The relationship between vel curve and dynamics controls . . .

Yes it can be complex in my opinion. I wish it wasn't, and naively used the velocity curve recommended for my keyboard -- which was causing me troubles. I don't have a solution, sadly.

I guess we should all take lessons from Phil Best (watch his video about the velocity curve setting if you haven't already). Since we're at it we can take playing lessons too :-)

I find the velocity curves help to make the antique pianos more realistic. For these, I find the moderately slow curve makes the piano a bit louder and the action quicker. Adding in a bit more duplex and resonance to the Schöffstoss, and the piano sounds totally different and more like the Katholnig I've played at the Frederick Collection.

Quicker lighter actions do take a bit to get used to, but you'll find that you need to play with more accuracy. This isn't such a bad thing because this technique translates well to other pianos without that because this technique requires a relaxed technique and a lot more control.

What really helps is playing firmly on each note to ensure there's a clear sound regardless of the volume being played. Using a relaxed technique with firm playing, takes a bit getting used to, but the results are amazing especially when playing Chopin and others from the Romantic period.

One solution might be to adjust your playing, instead of the piano.  Seems like that's what you'd do if you wanted to make things more "realistic".  At least assuming that Pianoteq's modeling includes the dynamic response of the pianos. 

Here's amusing video where a guy compares a Petrof, which he says has keys so lively it feels "like a race car", to a Steinway D, for which he says you have to lean in and "massage" the keys.  Skip to around 4:30 in to hear section I'm talking about:

https://youtu.be/1OfUxUIRcdA?t=272

I had to fix my post... I left out an important key element - the piano I was referring to. There's nothing like being interrupted while posting!

Anyway, yes, it's amazing how much can be done and how sensitive these instruments are compared to a modern piano. The historic instruments are amazing and playing them gives us a perspective of the past as well as what we play on today both digital as well as modern acoustic pianos.

Another piano I adjusted similarly is the 1853 Streicher (I think that's the date!). This is close in date to the ones I played from 1866 and 1871. The collection has an earlier one from the 1840s as well. Adding in a bit more of the same and using the moderately slow curve and the piano sounds more like the Streicher pianos I have played.

I have spent literally years trying to come up with a satisfactory velocity curve. Tell me about trial and error!!!

I have been at the point of exchanging my lovely P515 for something else several times, but that wouldn't solve the problem.

I know that Spectrasonics developers actually tested many currently available keyboards and controllers creating custom curves for them for use with their software. I wonder if Modartt could do the same. It is so difficult to the untrained like myself to create an optimum curve. Mybe we could persuade Modartt to at least consider doing this???

Warmest regards,

Chris

Pianoteq probably has a reference keyboard that allows to define the speed at which a key is pressed to obtain a certain velocity value. For each instrument a given velocity value will define a certain volume and a certain timbre as close as possible to the original piano. The straight curve is probably calibrated so that each instrument is realistic with the reference keyboard. It is this ratio of pressure speed value and velocity value that would be interesting to have.
Phil best shows another thing, that you can move away from the original curve to get other sensations. However, we can see that each modification of the velocity curve is associated with a modification of the hammer hardness, which is logical to keep a coherence between the touch an the brightness.
A standard key speed/velocity table would be welcome from pianoteq.
This would allow everyone to obtain a basic setting adapted to each keyboard (if for example at a defined touch speed our keyboard gives a velocity of 50 instead of 40 from the table it is easy to compensate by changing the curve).
I know there is the keyboard calibration assistant to do that, but how do you define "normal touch" "light touch" or "High velocity" ? It is very very subjective...
I know it is difficult to mesure key speed but I think it is possible with a camera or smartphone doing a low motion movie for exemple, then mesuring the time between High and bottom position of key.

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Yes, that would be very useful. I'd also like to see an interactive velocity monitor with a rolling graph, something like a loudness monitor but for MIDI velocity input.

I made some measurements of the speed of pressing a key on my keyboard. It is quite difficult to be precise, but here are the results. I made a video of a key at 120 frames/second, at various velocities. I then counted for each velocity the number of frames from the start of the key until its total depression. The difficulty is that the start of the key is very progressive at low velocity and the first frames are difficult to count. At high velocity the stroke is done in very few frames and limits the precision.
My keyboard is the Roland FP-10 (PHA-4 standard)

Velocity pianoteq  -  key stroke duration
            10                        400 ms
            20                        130 ms
            50                        100 ms
            70                          85 ms
            90                          75 ms
          110                          30 ms

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After more reflection I don't think that the measurement of the duration of the stroke is the most judicious parameter (too imprecise). The stroke of the key following an acceleration curve I think that the maximum speed at the end of the stroke is more interesting to know (the midi signal is sent in this zone of stroke).

Aproximate results :

Velocity pianoteq  -  End stroke velocity
            10                          75 mm/s
            20                         100 mm/s
            50                         240 mm/s
            70                          340 mm/s
            90                          380 mm/s
          110                          400 mm/s

Very clever method... I will try it... thank you...

And merry christmas. ..