Hex wire

[Paul S. Larudee]

Jim Coleman, Sr. wrote:
> 
> Low inharmonicity is not always the best as you indicate in your response.
> Good matching is better. Small pianos which use wound strings in the tenor
> section most always exhibit mis-matching problems. Attempts were made 100
> years ago to empirically solve this problem by using separate short bridges
> bridges for these tenor wound strings (mind you, this was before we could
> even spell inharmonicity). Continuity was lost. I have had some success in
> foreshortening wound strings in this area by simply fitting bridge material
> in front of the existing tenor bridge area. On a 6'4 Knabe, I was able to
> shorten the wound string area by approximately 3" for each note. This
> resulted in raising the inharmonicity of the wound string area to make a
> better match with the adjoining plain string area in the tenor section.
> 
The malleability and density of copper make it an excellent material for
wound strings when the objective is to achieve reduced inharmonicity. 
Heavier metals such as gold or lead would be even better for the extreme
bass and reduce the need for double or triple wound strings in smaller
pianos.  However, the obvious limitations of cost and toxicity make them
impractical.

As you point out, however, continuity of inharmonicity is a higher
priority than reduced inharmonicity at the plain/wound transition. 
Ideally, the core of the highest wound strings would be the size of the
lowest plain wire or reduced only slightly, with very minimal mass in
the windings.  The limitation, of course, is that below a certain gauge
the copper winding becomes fragile and unmanageable.  For this reason,
the mass of the minimum copper gauge requires a compensatory reduction
in the core wire mass (i.e. gauge), hence greater flexibility in the
string and reduced inharmonicity.

This need not be the case if lighter metals such as tin are used instead
of copper for the highest wound strings.  We can use the same gauge of
cladding as we always have, but the material will be much lighter, which
allows a heavier core more similar to the adjacent plain strings.  This
makes for a smoother transition.

Is there any reason all the windings have to be of the same metal?

Paul S. Larudee, RPT
Richmond, CA