[CAUT] Sperrhake Harpsichord wire

[Fred Sturm]

On Dec 5, 2009, at 12:43 PM, Ron Nossaman wrote:

> Fred, I still don't know what you're talking about. We've talked  
> about break% for years and years and it's always been percentage of  
> breaking tension at the string's current tension. How about posting  
> the formula from your spreadsheet, as I did from mine, so I can see  
> what you're doing?
> Ron N


 From the "Collins" spread for tension:  
=((StringL*FreqP1*CoreDia)^2)*(CoreDens*PI())/(9.81*10^12)*(1+ 
(IF(ISBLANK(CovDia),0,1))*((CovDens/10000)*(((CovDia^2)/ 
(CoreDia^2))-1)))

% break:
=IF($D$5="Röslau",100*L19/LOOKUP(F19,$AA$20:$AA$60,$AD$20:$AD$60), 
0)+IF($D$5="Pure Sound",100*L19/LOOKUP(F19,$AA$20:$AA$60,$AC$20:$AC 
$60),0)+IF($D$5="Malcom Rose C",100*L19/LOOKUP(F19,$AA$20:$AA$60,$AB 
$20:$AB$60),0)

For the "Roberts/Rhodes" tension:
=(RC[-9]*RC[-8]/802.6)^2*2^((RC[-10]-(440-R11C2)/(440-415.3))/ 
(6))*(RC[-6]*(RC[-7]^2/RC[-8]^2-1)+1)
% break
=RC[-4]/(0.557*RC[-12]^1.667)*60

Which isn't exactly the formula, and if you can decipher it, you are  
doing better than I am. The Roberts uses inches, Collins is metric FWIW.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu





-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ptg.org/pipermail/caut.php/attachments/20091205/8d70df0c/attachment.htm>