Killer Octave & Pitch Raise

David Ilvedson ilvey@sbcglobal.net
Sat, 12 Feb 2005 11:39:56 -0800


I will mention an interesting tip I got from yesterday's class with Roger Jolly.   It was a voicing class but he made an aside that when restringing he uses a padded piece of wood to smack the bridge as he progressed, from the front side to possibly help counter bridge roll?   He didn't know if it did a thing for sure but that's what he did...

David I.



----- Original message ----------------------------------------
From: Michael Gamble <michael@gambles.fsnet.co.uk>
To: Richard Brekne <Richard.Brekne@grieg.uib.no>
Received: Sat, 12 Feb 2005 15:50:50 -0000
Subject: Re: Killer Octave & Pitch Raise


>Hello Ric
>Interesting post - and one which affects all who undertake the restringing 
>of pianos. In order to comply with the best proceedures with relation to 
>bringing a piano down to remove the old strings - and, more importantly??, 
>bringing the piano back to A=440 what, in the interests of your post, do you 
>believe to be the best course of attack? Please take it step-by-step if you 
>would be so kindly! So you're face with restringing an S&S model D........go 
>from there!
>Regards
>Michael G (UK)
>----- Original Message ----- 
>From: "Richard Brekne" <Richard.Brekne@grieg.uib.no>
>To: "Newtonburg" <pianotech@ptg.org>
>Sent: Saturday, February 12, 2005 12:54 AM
>Subject: re: Killer Octave & Pitch Raise


>> Udo Steingręber and I got into a conversation about this in Helsinki a 
>> couple years back on the only opportunity I've had to sit and chat with 
>> him.  It was part of a discussion where he was explaining why he felt 
>> compression soundboards were the way to go.  He mentioned something about 
>> the so called K point (I think this is a Klaus Fenner coined term), which 
>> as I understood it was that point on the soundboard where crown from both 
>> along the grain and cross the grain intersect and is at its highest point. 
>> This area is exactly (and always) in the area typically refered to by 
>> american techs as the <<killer octave>> area, and of course varies 
>> somewhat from piano to piano.  It is then  also the exact point then that 
>> is most vunerable to failures.  Udo was of the position that along the 
>> grain crowning was every bit as important as cross grain crown.  Something 
>> to do with along the grain compression due to downbearing having a 
>> stablizing effect on cross grain crown and strength.  He also meant that 
>> both these were needed to produce the kind of acoustical results he wanted 
>> from a soundboard.
>> I'm under the impression, correct me if I am wrong, that most of the rib 
>> crowned methods extoled on this list do not employ any purposefull along 
>> the grain crowning as part of how the panels are attached to the rim, and 
>> therefor do not have this vunerablity.  It would stand to reason that they 
>> too are not able to create the same acoustical  results.... (whether that 
>> is preferable or not is an entirely different subject).
>>
>> Disclaimer.  This description is my understanding of what Udo was saying, 
>> tho I beleive it is pretty accurate. Not being a soundboard engineer tho, 
>> I'll leave it to more experienced to explain, interpret, or whathave you 
>> the above.
>> One other thing tho... I've always heard that large changes in pitch, and 
>> destringing / restringing proceedures should be carefull of this area.... 
>> making carefull changes that are appliled very evenly,  exactly because 
>> this area can easily be damaged by sudden large changes in the stresses 
>> applied to the panel as a whole.  Seems to jive well if the basic view 
>> above  is correct to begin with.
>>
>> Cheers
>> RicB
>>
>>
>>
>>
>> 


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