[pianotech] Steinway A Bass String Rescaling

JUDE REVELY juderev at verizon.net
Mon May 25 20:33:27 MDT 2009


I've been off the grid for the Holiday weekend and apparently have some 
clarifying to do so here it goes...



There have been three attempts to the best of my knowledge to formulate 
inharmonicity; by Jim Hayes, Dave Roberts and Dr. Al Sanderson. Although 
imperfect, I believe the point was certainly to demonstrate the deviation of 
a specific partial, typically the fourth, from the mathematical ideal to a 
practical application as a result of stiffness, as defined by a function of 
the wire length, material and tension.



Yes, this is only one indicator and is not independent.  In analyzing or 
designing scales, we have the properties of a scale that we can manipulate, 
namely the wire material, core diameter, and length as well as the wrap 
material, type and diameter and the various wound string inharmonicity 
controls such as the bare length, steps and types of whippings. Then we have 
the results or qualities that are a result of these scale properties. 
Inharmonicity, tension, breaking %, Z, and hammer to string contact time are 
ones that have been traditionally examined, but do not by any means 
encompass the whole picture.



As for inharmonicity, while it is my belief that there will be future 
improvements to this formula; for now it is still worthwhile that we 
continue to examine it rather than discard it altogether. As mentioned, 
managing inharmonicity is important for smoothing the transition over 
breaks, but I also think you can hear the results of the proper management 
of inharmonicity through reconciling beat rates within a tuning. I standby 
my statement that there are practical ranges for inharmonicity, although I 
hope that it is clear that this is indeed a by-product of other 
considerations. My order of priorities is tension, inharmonicity, acoustical 
power, than breaking % so long as it remains in a practical limit.



I'll see if I can find out more about the scale of the "zero inharm bass 
strings" before invoking it again; but let's face it, it's better to get 
this stuff out into the light rather than suppressing it altogether.



Finally, I do apologize if my reference to "string theory" in quantum 
mechanics was perceived as misdirection. I was just being punny.



Jude Reveley, RPT
Absolute Piano Restoration, LLC
Lowell, Massachusetts
(978) 323-4545 



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