Ian, warum sollte das Klavier "wissen", was richtig ist? Warum sollten Zahlen nicht wichtig sein? "Weiß" das Klavier, was Vorbesitzer oder Techniker im Laufe der Jahre alles eingestellt oder verstellt haben? Was verschlissen ist? (Hammernussleder, Hammerleistenfilz...) Es kommt doch auf den guten Zustand der Bauteile an, und auf die Kombination aus Hammerweg, Auslösung, Mechanik- bzw. Hebelverhältnis und Tastentiefgang, und dem daraus resultierenden Nachdruck. (Wenn das der richtige Ausdruck ist.)
Ian, why would the piano "know" exactly what's right? Why would numbers not matter? Does the piano "know" what previous owners or technicians have adjusted or mal-adjusted? What is worn? (Butt leather, hammer rail cloth...) Surely it's the condition of the components that matters, as well as combination of blow distance, let-off, action ratio and key dip, and the resulting aftertouch?
Mark
This is a long post in answer to your questions. I hope you won't mind translating it.
When I asked the
Piano World forum what the optimum key dip might be for my piano, two well respected technicians said forget the numbers and regulate it so that it feels good. Similarly Michael said here that the Steingraeber played as well as the best pianos of today. No numbers!
That was very useful advice but what also helped me was the suggestion that 0.5 mm after touch was probably insufficient for good feedback and control. This proved to be right; I found 0.75 mm was better than 0.60 mm (loss of control)and 0.90 mm (loss of feedback).
A previous technician had lifted the hammer rail and reduced the blow distance (by about 4 mm). When the beaten up Ibach arrived last month its range and volume soon told me the Schiedmayer did not like the way it had been set up. It wanted to get back as close to its original state as possible. I put the hammer rail down again, pulled out all the oversized punchings the technician had added, set let off close to the strings, and the piano became a Konzertklavier again, ppp to ffff.
The problem was the key dip was too much, at well over 11 mm when I measured it. Blow distance was normal, roughly 45 mm. The simplest thing to do was to increase let off to about 3 mm. So you see, I did pay attention to the numbers.
The piano knew its action was in its original position and it would perform as well as it could in its current condition. Luckily the hammers and the hammer rail cloth had not worn much. The points at which the jacks escaped would tell me how much after-touch and key dip I had to play with.
My first step was remove all the punchings from the front pin of a test key, replace the felt, then add punchings until there was zero after-touch when I pressed the key slowly. This was the point where you see the hammer is closest to the strings and the jack is just escaping from the butt. The punchings were 1.75 mm thick.
Next, I tried after-touch at 0.50 mm, 0.60 mm, 0.75 mm and 0.90 mm. I preferred the touch and feel at 0.50 mm but 0.75 mm was better for ppp. This means the piano in its current condition needs about 1.00 mm of punchings under the felt for "optimum" key dip.
Finally, I found it beneficial to increase the let off on some keys by a tiny amount to ensure all the jacks escape quickly at pp. It is very easy to see which jacks need adjustment when you watch them escaping.
I measured the key dip afterwards with calipers, 11.0 mm at the front pin. Blow distance, 44 mm. When the let off button is raised so the jack never touches it, it takes 11 mm of key travel to produce 44 mm of hammer travel. To my mind this makes the overall action ratio 4.0 but the action is not linear so the ratio, however you calculate it, may only be useful as an indicator.
Thilo would prefer to see let off at 2 mm instead of 3 mm. To allow for this I could reduce blow distance as he suggests - to 43 mm. Another possibility is to reduce after-touch to 0.50 mm. When I give the action a full service I may be able to reduce the friction of the jacks and with the butt leather and the let off button felt. The graphite on the jacks certainly needs checking.
Your final point is about "resulting after-touch". One of the experts on Piano World made exactly that point. He said "Actually you do not set the after-touch! After-touch is the result of a well regulated action". Others take steps to set consistent aftertouch, including the
Yamaha Academy - André Oorebeek once posted "There was a time in my professional life where I had a complete break through. It was when I learned that a hammer travel distance gauge is not necessary anymore.… At the concert grand level, regulating the 'final' hammer striking distance is one of the last procedures during regulating."
I hope this answers your questions.
Greetings
Ian
Hab ich damals in der Big Band immer äußerst gerne gespielt :wink:
