Introduction and problem: beats already present with a single string

everything to be seen. First of all, one must see if the string rests well on the bridge. I advise gently tapping the string, perhaps with a brass bar and soft metal so as not to damage it, at the position of the pins on the bridge. If the phenomenon disappears, ok. It could be an error in the driving of the pin relative to the cut of the bridge. In this case, there is nothing to be done because it is as if two slightly different lengths were vibrating: one that goes from the nut (or aggraffe) to the bridge pin and the same one that goes from the nut to the bridge cut... hence the beat. Another cause could be rust on the string... but unlikely. Anyway, in the future, post questions in the appropriate sections, thank you.

Maestro, I thank you for the response and I apologize if I combined the introduction and the question into a single post.

In fact, the question would be more visible to other interested parties if it were in the Tuning section.

Since I intend to perform tests and provide feedback, would it be possible to move/re-post the post (perhaps only the question part) to the Tuning section?

Thank you

Good evening.

I have conducted careful tests, but it is not easy to understand the situation, especially because striking the string with a soft iron (not having anything else, I used a crochet hook) does not yield the same quality and power of sound as the hammer.

In any case, it seems to me that the sound on the free string is good.

Moreover, I encounter the problem from D5 to F6, and I find it difficult to believe that YAMAHA could have released a piano from the factory with such manufacturing problems.

Rather, I would like to add some background to the matter that might perhaps shed a different light on the issue.

A few years ago, I had the unfortunate idea of calling a technician to have the mechanics checked but, in the time it took me to prepare him a coffee, he had already begun, on his own initiative, to shave the hammers. When he finished, he tuned the piano and left without even having performed the voicing procedure. I called him saying that the piano no longer sounded, that it had lost its voice. He replied that playing would produce grooves on the hammers and that after a month it would return to normal. He came back, finished, resolved nothing, and I did not call him again: he couldn't do anything, he wasn't capable.

Desperate, I finally managed to get in touch with a real technician who, with about eight hours of work in total, gave life and voice back to the piano. Among the various interventions, he aligned and voiced every single hammer. Since then, I have always called him.

Now I wonder: is it possible that the hammers could be causing the problem? Is it possible that the alignment, or I don't know what else, needs to be rechecked?

Thank you.

from a distance it is impossible to evaluate! Anyway, I am personally against shaving, which, moreover, is often performed incorrectly, i.e., by rounding the hammers too much. Furthermore, by shortening the hammers, the geometry of the action and the striking point change. This latter modification may have generated some unpleasantness when listening even to a single chorus, especially in the mid-high range. One must consider that the piano is of modest size and the slightest shift in the striking point can be critical. I recommend replacing the hammer rail and.....never shave it again!