Another possibility, if the Grotrian was made around the seventies, is that the bridge was designed with insufficient spacing between the unisons. This problem results in insufficient wood around the pins to properly support the side bearing forces. With an example I have experienced, several unison strings are so close to the pin of its neighbouring unison that noise (metallic in character) is generated at the bridge during heavier playing. The source of this noise can be confirmed by holding a blade screwdriver between the suspect bridge pins. In 1988 one of my clients purchased a new bridge cap from the factory for his Grotrian 223 grand when he visited Germany. In hindsight, I wish we had ditched the replacement cap and laid out a new design. But its easy to be wise after the event. When my clients son inherits the piano there are plans to recap the bridge again, but the board is starting to exhibit symptoms of failure, so it could end up being a total board redesign. Ron O. >On 10/16/2010 1:43 PM, Robert Callaghan wrote: > >>It is a Grotrian grand and has a beautiful sound with all >>types of playing except this one note on heavy playing. I began to >>suspect the bridge cap, but this sound is metallic. > >Three things. Is the slant of the speaking >length bridge pin around 20°, or nearly >vertical? Is the string offset angle across the >bridge top around 10°, or nearly straight (I'm >guessing nearly straight, from the description)? >Is the downbearing angle there positive, if >there is any? > >Sounds to me like the string is slapping the >bridge pin from lack of, at least, side bearing. >Ron N -- OVERS PIANOS - SYDNEY Grand Piano Manufacturers _______________________ Web http://overspianos.com.au mailto:ron at overspianos.com.au _______________________
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