[CAUT] Re. Link to Young Paper

RicB ricb at pianostemmer.no
Thu Jan 18 13:29:11 MST 2007


Thanks both Fred and Jim for the exchange of thoughts. 

A couple comments to both you..  First Fred mentioned a bit about 
finding anomalies in plain wire strings as well as wound.  I havent 
mentioned anything about this before, but using Tunelab like I do I've 
been noticing more and more that the entire unwound section is subject 
to para-inharmonicity problems to a much more significant degree then 
ETD authors let on.  Not that the ETD doesnt do a good job mind you... 
totally different discussion... but there ARE unexpected divergences in 
the unwound string from expected partials frequencies given the 
inharmonicity of the instrument. And sometimes... just shy of often I'd 
say... they have to be taken into account if you want that <<perfect>> 
tuning.

To both of you.. and anyone else out there.  I remain miffed about this 
basic quandry of Youngs origional inharmonicity formula and its demand 
that the Youngs Modulus divided by String Density should equal 
25.5*10^10 when virtually no give data set for these two parameters 
yields anything really close to that. 

Thomas Young demands that  Q/p = 25.5*10^10

Look up various specs for steel wire around the net for Youngs modulus 
and density of piano wire... plug in the values and check it out.  To 
begin with there is a large variation of specs for the Youngs Modulus... 
yet virtually everyone agrees that density is about 7.85 g/cm^3.  By the 
book then... if density is indeed 7.85... then Youngs modulus should 
work out to close to 2.00175 * 10^12. 

I'd love to hear an explanation about why theory and  <<measured>> specs 
seem soooo far off from each other, and what to do about it when 
thinking about designing scales.

Cheers
RicB


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