Wire Preferences

[Stephen Birkett]

Dan Squire wrote:
>
> Interesting, flexibility is defined as the elongation due to a unit
> load.  Flexibility is the inverse of stiffness.  By definition, this
> means that the flexibility is inversely proportional to the modulus of
> elasticity.  Therefore, according to your statement, these different
> brands of wire have different values for their modulus of elasticity.
>
Stiffness, as it relates to inharmonicity, depends on more than just
the Young's modulus (of elasticity), which is a property of the
material of the wire. In the context of inharmonicity, stiffness,
the resistance of the string to bending, is proportional to:
  the square of the diameter;
and inversely proportional to:
  the square of the stress frequency
  the 4th power of the length
As well as these parameters which vary obviously across the scale,
stiffness is also proportional to the modulus of elasticity and
inversely proportional to the density, both of which are properties
of the wire material and don't appear to vary significantly amongst
different modern wire samples (at least compared to the wide
variation in stiffness due to scale). Thus to reduce stiffness (and
hence lower inharmonicity) would require the string to be as long, as
thin and as taught as possible.


Stephen Birkett (Fortepianos)
Authentic Reproductions of 18th and 19th Century Pianos
Waterloo, Ontario, Canada
tel: 519-885-2228
fax: 519-763-4686