whatkindapianoisitanyway?

Horace Greeley hgreeley@leland.Stanford.EDU
Thu Jun 4 21:52 MDT 1998


Tom,

Thanks!  That's what I was after.

The modern wire is stronger, if all one is after
is tensile strength.  The older wire had, among
other documented differences, more nickel.
I am not enough of a metalurgist to know with
specificity what reductive difference that makes.
I do know that it was easier to maintain whatever
pitch level (relative to 440) one wanted to, without
worrying so much about the affect on the tone - 
which, to my ear, almost always seems to be
more centered in the lower partials of the pitch.

This is right in line with the Gertz and CFT Steinway
patents that talk in terms of 50% of the energy in the
fundamental (first partial), then 50% of that 50%
in the second, then 50% of _that_ 50% in the
third, etc.  

I wonder, would this designed concentration of tonal,
in combination with, for example, a more malleable
wire, make for instruments which could actually survive
higher tensions longer, with better tone (whatever
_that_ is) than instruments designed for higher tensions
(to begin with) which also happen to have harder wire?

I know, I'll go away now...

Best.

Horace




At 11:29 PM 6/4/1998 EDT, you wrote:
>Hi, Michael -
>
>Here's a stab at an 'intuitive' answer to your question:
>
>If you leave everything else the same (i.e., length and tension), increasing
>the diameter of wire will also increase the mass.  This will lower the
>vibrating frequency.  You can compensate for the lowered frequency by
>increasing the tension on the larger diameter wire - BANG!
>
>Both the vibrating frequency and the breaking strength are related to the
>cross-sectional area of the wire.  Increasing the diameter gives increased
>strength, but lower frequency.  It's a trade-off that you cannot win if the
>speaking length is too long - which it is in your example.  Since the piano
>presumably worked at one time, but not now after rebuilding, I'd suspect that
>the relationship between the bridge and plate has changed.  In other words,
>the strings are slightly longer now than originally.
>
>I like Horace's hypothesis about the magic in 19th c. wire.  That's certainly
>well documented as regards 17th c. harpsichord wire.  However, I think
that in
>both old piano wire and old harps wire the charm lies in the warmth of tone,
>not in superior strength.  I think modern music wire is probably the
strongest
>yet.
>
>   -     Tom McNeil, RPT     -
>Vermont Piano Restorations
>
>
>In a message dated 98-06-04 13:56:38 EDT, you write:
>
><< ts a shomer grand.
> 
> You should ignore the column that has the gauge of the wire listed.  My
> point is well taken with Mr. Greely's contribution, gauge has nothing to do
> with the breaking point of the wire even though it seems it should have
> everything to do with it.
> 
> Equation for tension is:
> 
> Tension = (frequency^2 + Length^2 + diameter^2)/434
> 
> Equation for Break pt.:
> 
> % break point = tension/(2528 * diameter^2)
> 
> So the diameter^2 in the denominator of the "% brake point" equation
> cancels out the diameter^2 in the tension equation.  So % brake point is
> independent of the diameter of the string. This means you can try all kinds
> of gauge sizes and it will never alleviate the string brakeage problem.
> Now, this seems counterintuitive to me but I know its right. Can someone
> explain it?
>
>Michael Wathen
>
>
Horace Greeley, CNA, MCP, RPT

Systems Analyst/Engineer
Controller's Office
Stanford University

email: hgreeley@leland.stanford.edu
voice mail: 650.725.9062
fax: 650.725.8014


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