Hello, assuming that I am not a technician and understand very little about mechanics, I wanted to ask for opinions regarding my Kawai.
I recently purchased a splendid, fairly recent (1994) Kawai KG2, not refurbished, with an intact keyboard and action; the only flaw of the instrument was a "deadness" in the penultimate octave of the treble (the so-called "Killer Zone").
After several inspections, my tuner worked on this octave by shaving and propping up the affected hammers with needles, managing to bring out a bit more sound; the problem is that now some of these sounds are very METALLIC and it is as if they were WHISTLING, in addition to not guaranteeing tonal uniformity; the problem is emphasized when I engage the Una (soft) pedal.
How could I resolve this problem?
By playing on it, could the sound improve over time?
From what you are telling me, I would not have shaved the hammer rail yet... and certainly not partially!!!! One needs to see what shape has been given to the hammers and how they have been voiced. Perhaps it can be saved. I hope that the striking point hasn't been rounded too much, which in this case could not be "recovered" and improved. I would have compacted the hammers, proceeding also with a smoothing and a new voicing, instead of trying to find a new hardness of the felt in depth. If a string sounds metallic when the pedal is pressed, it can be a symptom of bad voicing or imperfect planarity of the hammer's striking surface relative to the string. This would need to be seen before any further intervention. In the most extreme case, the hammer rail will have to be replaced shortly.
If the hammers do not sound on the high notes, they need to be shaved to a point; if that is not enough, the felt must be compressed, and if that is still not enough, it must be impregnated.
Obviously, you must check that they strike at the correct point! Have you tried moving the action back and forth by one or two millimeters?
Do the strings sound good if plucked?
I don't understand why he started poking it though.... Did he think he would open up the sound with a needle on a high hammer?
Dear Fra, I avoided suggesting moving it precisely because the shaving was partial (this would change the strike point differently between the hammers)! This can be done, in fact, it must be done when the shaving is total. Anyway, it's a matter of opinion. I do agree, however, on the prickling. On the high notes, prickling is risky, especially when the felt is being shaved. Naturally, the high notes must be pointed... assuming there is enough felt to restore this shape. Perhaps some photos would clarify this aspect.
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Fra
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Reply 6 by Fra
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Of course, I was assuming that even before shaving someone, they had moved the small plate to the right block! You never know in these cases. Before proceeding, I would have checked if the action was positioned correctly.
But strange! On recent and original pianos, it almost never happens that the last octave is dead, especially on a Kawai! It happens more often when a new hammer rail is installed.
Well yes, of course. The last octave would need an impregnating agent, especially the last 5-6 keys. The hypothesis is that it could have been excessive moisture absorption. Here we are talking, however, as I understand it, about the penultimate one. And then... it could have been "softened" by some technician in the past, with a consequent loss of the hammer's "head strike wedge".... Bah!
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Fra
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Reply 8 by Fra
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The penultimate one? Then it must have been sabotaged.....
Anyway, even with new instruments, it happens to find some sections weaker than others. A teacher in Varese had purchased a new Steinway, an 188 I believe, with a 40% discount off the list price. She complained of a lack of sound specifically in that section.
Going under the piano, it could be seen that at the strings corresponding to the high notes, the flare (widened) had been modified, probably in post-production because they noticed the defect and tried to make the soundboard less rigid to make it sing more, but it wasn't sufficient (it's probable it turned out even worse, I don't know).
You should always listen to them carefully in the shop, perhaps spending 100 euros for a consultation from an expert because defects show up when the piano is already home, where it can be remedied but only to a limited extent.
