On the notes between the fourth and fifth octave, I perceive an annoying dissonance, as if the sound were distorted.
Tuning did not resolve anything and the technician says that voicing would be useless in this case.
According to him, it could depend on some panel or some screw that is vibrating.
i tried to dampen one or two strings for each key with a small piece of paper, and the dissonance is reduced or disappears completely, but in this way the sound becomes less intense.
It's all something to see... actually, to hear, but in person. The technician must decide and report back to the dealer that they can replace the instrument for you. Try changing the piano's position anyway; sometimes it also depends on its imperfect support on the floor. If stopping a string makes the problem disappear, it could depend on the settling of the string on the bridge or the hitch pin, or on the nut if we are in another area. It could also depend on the back-string. Satisfactory hypotheses cannot be made from a distance.
