Wotl wrote:

I noted that when using the virtual keyboard of the app, I have a crystal clear high volume sound, while when I”m using my Kawai ES60 or my Yamaha CP88 the sound volume is lower and like if I have an una corda pressed. Why this difference ?

That's presumably because the way the virtual keyboard note-on velocity profile is different from your own digital pianos. When you press a key on the virtual keyboard at the extremity of the key closest to the key slip  , you get 127 as note-on velocity even with a light pressure, when you press a key at the extremity of the key close to the fallboard you get very low velocities. You have to hit keys very hard to output a note on velocity =127 (on some DP's it is even impossible unless you change the velocity curve in the DP itself ).

Thank you for this information

I noted that when using the virtual keyboard of the app, I have a crystal clear high volume sound, while when I”m using my Kawai ES60 or my Yamaha CP88 the sound volume is lower and like if I have an una corda pressed. Why this difference ?

That's presumably because the way the virtual keyboard note-on velocity profile is different from your own digital pianos. When you press a key on the virtual keyboard at the extremity of the key closest to the key slip  , you get 127 as note-on velocity even with a light pressure, when you press a key at the extremity of the key close to the fallboard you get very low velocities. You have to hit keys very hard to output a note on velocity =127 (on some DP's it is even impossible unless you change the velocity curve in the DP itself ).