Pure Tone Strings

[Richard Brekne]

Ok... this makes things very clear indeed, and looking at the Inharmonicity formulas
I have makes perfect sense when its first explained so neatly.. grin.. Thanks
Stephen. You mention at the bottom of this that the alloy affects tone in another
sense.  Since you lead on....grin... what might this other sense be ?? How is it
percieved ??

Very greatfull for your time in writing this down. You no doubt have done so many
times before..:)

Stephen Birkett wrote:

> Richard asks:
> > Ok you guys... you got me confused a bit here... Perhaps I misread .... On the
> > one hand it is stated that Inharmonicity is a function of the stiffness of the
> > wire which is a function of length and tension, then on the other hand it is
>                             ^^^^^^^^^
> Here's the mistake Richard. Stiffness is a bulk property of the material
> (alloy) out of which the wire is made, and to a _much_ lesser extent, a
> function of the drawing processes which the wire undergoes in its
> manufacture. Stiffness is expressed in terms of the Young's modulus of
> the wire material. Typical values are 230 GPa (modern steel music wire),
> 190 GPa (repro. mild steel wire), 160 GPa (historical iron wire), 100 GPa
> (historical yellow brass wire - no lead!). Stiffness is a measure of the
> elasticity of the wire material and is not affected by stringing
> parameters such as length, diameter, or tension.
>
> > stated that a change of stiffness of up to 50 % will have a neglible
> > effect on inharmonicity... explain this a bit if you may ???
> >
> Inharmonicity is a function of stiffness, length, diameter and tension.
> Since length operates at the fourth power it is the primary determining
> factor in determining the inharm. at a given pitch. Or, you can think of
> inharmonicity being determined mainly by the length to diameter ratio.
> (The trebles of short-scaled big Viennese pianos have astonomical values
> for B.) The effect of the stiffness parameter on the value of B (inharm.
> coefficient) is almost insignificant by comparison. Variation from
> brass to modern steel has very little aurally perceivable effect on
> B.
>
> > Btw.. another claim made on this phone call was that the inharmonicity was
> > more predicitable. Ie conforms better to the inharmonicity formulas out there.
> > He might have just been throwing me a bit of a sales line here.. but well...
> > comments ?
> >
> That was a sales pitch for sure. The alloy has little effect on
> inharmonicity. It affects tone by another mechanism.
>
> Stephen
>
> Stephen Birkett Fortepianos
> Authentic Reproductions of 18th and 19th Century Pianos
> 464 Winchester Drive
> Waterloo, Ontario
> Canada N2T 1K5
> tel: 519-885-2228
> mailto: birketts@wright.aps.uoguelph.ca

--
Richard Brekne
Associate PTG, N.P.T.F.
Bergen, Norway