Bald Ham Pitch Swing

[Richard Brekne]

Ron... I wonder if you might extrapolate a bit on what you mean exactly by
"breaking string deviation"  A couple more paragraphs ought to do it... grin.
Interesting post

Richard Brekne
I.C.P.T.G.  N.P.T.F.
Bergen, Norway

Ron Overs wrote:

> Hi list,
>
> The lower tenor and either side of the treble (strut) break are, in many
> pianos, designed with string lengths which produce wide variations in the
> percentage of breaking strain when at pitch. This will result in the
> pitch deviating more in response to soundboard movement when humidity
> changes. Furthure, if the downbearing angle lacks uniformity these pitch
> variation will be more pronounced.
>
> We have measured over fifty different piano scales over the years. There
> is a definite relationship between the overall deviation in the
> percentage of breaking strain, and the tuning stabilitiy. While other
> factors also have an influence, the most carefully manufactured piano
> with a large deviation of breaking strain will always exhibit poor tuning
> stability,  eg. Yamaha U3.
>
> The Yamaha C7F, which has much less breaking strain deviation when
> compared to previous models, has much improved tuning stability.
>
> A comparison of the scales of a Kawai KG6 and a Steinway model D will
> show that the Kawai has apprximately 10% less deviation in the percentage
> of breaking strain accross the scale. A well rebuilt KG6 will always
> exhibit superior tuning stability to a well rebuilt model D. It is all a
> matter of scale.
>
> Regards to all,
>
> Ron E. Overs
>
> Email: ron@overspianos.com.au
> Website: www.overspianos.com.au