three keys in the bass register produce a high-pitched background noise, similar to the tinkling of a teaspoon hitting a cup. If the key is pressed softly, the noise is not heard; if pressed hard, it becomes more evident. Key number 15 has only one string, but the other two keys have double strings, so I blocked the string that was producing the noise with a small piece of rubber. In this way, the high-pitched sound disappeared on two of the three keys, but it is only a temporary fix. The hammers in the central area have grooves about one millimeter deep, whereas in the bass section the grooves are less pronounced.
The piano is a 1976 Schimmel upright. It was purchased new in '78 and has been used very little. It was tuned last year. Previously, it had only been tuned once, thirty years prior. I started using it last year for almost three hours a day, every day. Now I am starting to encounter these problems.
Generally, if it happens in the bass strings, it could depend on a deviation of the copper winding in one of the two terminal parts of the string. The fact that the noise disappeared by isolating the string does not make me think of a bridge detachment. The technician should, using pliers and without loosening the strings in question, turn and tighten the copper in the direction of the winding. If the defect does not disappear, it is advisable to change the defective strings. Careful, I recommend changing both strings of the same note. The strings must be specially made, respecting the diameters of the steel and the copper and not just the total diameter. Exactly the same type of eyelet! In short, made in a laboratory and not derived from ready-made strings to be unraveled! I hope the problem is resolved. The Schimmel is a beautiful instrument!!!
It can happen that it "slips" on its own, because the winding was not properly seated at the closure points; it can happen that it becomes loose accidentally if it is touched even with a tuning hammer, over time, especially in the thin strings closed with zigzag winding, to be precise.
In my opinion, the safest string from this point of view is the one closed with a flattened copper loop (pointed) as Steinway does, for instance...
If the copper has slipped, it can alternatively be removed if there is little of it (one or two turns) and cut by pulling it with pliers in the direction of the winding to perform a new closure.
If that doesn't work, the string must be redone as I said; it is absolutely right to redo both strings if the unison is double, otherwise there will be a difference in timbre that can make them impossible to tune!
Well, it doesn't make the situation worse, but perhaps in the fortissimo or forte the defect could become more pronounced. In any case, the sooner you intervene, the better. It's no small thing to try tightening the windings!
