Ed Sutton writes: > Action saturation. > As the pianist plays harder, the action parts flex more, so that > eventually > the force delivered to the string is determined by the whipping movement > of > the parts rather than the speed of the stroke to the key. The acceleration > of the hammer has reached its peak. The pianist plays harder, but the only > sound that gets louder is the thump to the keybed. > There is a great example of this in the "Five Lectures" series. By comparing timing of the action components during varied levels of force, it becomes apparent that at some point, the key is hitting the punching well beore the hammer has finished its acceleration. Taken to an extreme, it is possible to bottom the key out before the hammer moves much at all. Which means that the force hitting the string is limited to whatever compliance is found in the action. I think the key is responsible for most of this, though the hammershank would run it a close second. The balance rail punching, capstan felt, and knuckle compression would come in third, with the small amount by rail flex and pin bushings contributing a little more. Regards,. Ed Foote RPT http://www.uk-piano.org/edfoote/index.html -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20100728/3141e124/attachment.htm>
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