Hello list, I am curious if anyone uses a math model for finding the strike line and arrives at a line that gives the best tone. Also, if listening is included in the model, exactly what are we listening for in what part of the piano? I have read Wolfenden's technique that says to start with 1/8th at the lowest note and graduate to 1/9th at 52, 1/10th at 64, 1/12th at 76 and 1/14th at 88. The original strike line on my Knabe was not even close. (It is now restored with new board, bridge, strings and hammers.) My samples are notes 1, 47, 68 and 88. Note 1 sounds much better at 1/8th and is farther toward the bridge than original by about 4.5mm. Note 47 also sounds much better at 1/8th and is about 2.5mm longer than original. Note 68 and 88 are a bit more elusive. I move 68 from the original fore and aft 1 to 3mm and can hear very little audible difference - it sounds good anywhere in there. Actually, the closer the hammer comes to binding on the belly rail the better it sounds. Note 88 appears to be good enough at about 3.3mm about 1/16th - it just is dead at 1/14th. It is clear that listening is a key part of this but are we really trying to hit a node and eliminate the odd partials like 5,7 and 9? Wolfenden says and it makes sense, this is not really an issue in the upper section above middle C. On a side note: I did alter some speaking lengths for a couple of reasons: note#1 was shortened by only 1mm and note #88 was lengthened by 5.3mm and I used 1.05 as a multiplier to correct speaking lengths down to about note 60 and after that I lengthened speaking lengths as much as practical to get the tensions higher down to about F3. These were small changes but were improvements. So I know that the strike line should conform to a more ideal math model and certainly would differ from original. Now I struggle to fined this strike line. Anyone care to share their technique or thoughts? Certainly this all will change the action geometry as well. Thanks Gene Gene -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090208/85d1e1f6/attachment.html>
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