String leveling as related to tuning

[Richard Moody]

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> From: Bill Ballard <yardbird@sover.net>
> To: pianotech@ptg.org
> Subject: Re: String leveling as related to tuning
> Date: Wednesday, April 08, 1998 9:36 PM
> 
> On Wed, 08 Apr, Michael Jorgensen <Michael.Jorgensen@cmich.edu>wrote:
> >Hello List
> >   Fast test blows help level strings?
> 
> If fast test blows could level strings, what would prevent them from
> continuing to push all three string in a trichord upwards.That seems to
fly in the >face of the
> wire's elasticity.

The whole concept of leveling strings seems to fly in the face of the
nature of the wire's elasticity. If strings are out of level because of
wear or defects in agraffes or pressure bars, how is bending the wire,
going to last? There is for music wire two measurements of importance, the
breaking point, and the elasticity limit. Elasticity limit means the wire
is stretched to a point that it no longer returns to its original length
when the tension is released.  W.V. McFerrin refers to this as elongation.
One of the properties of enlogation discussed by others is narrowing of
the diameter of the wire at a certain point. Another point is the effects
bends have on wire. Bends occur at what some refer to as "pressure points"
and these are at the agraffe, the tuning pin, the bridge pins and the
hitch  pins.  These bends in my hypothesis, are also elastic, but are on
the verge of elasticity, and will quickly loose elastic properties if
stretched beyond their elastic limit.  But I don't know how to porve that.
  Now if a wire is bent to make it level, what does this do to its
acoustic properties? The theories of Helmholtz involving the partials, and
Young's modulus of elasticity used in predicting inharmonicity are based
on straight elastic music wire.  Keep in mind the bends of the wire at the
pressure points by Moody's conjecture also contribute to the wire's
accoustics, so how may  bending to level the wire affect these? .  
	Well that is all theoretical, in practice maybe it doesn't matter if the
wire has a slight bend in the speaking length. Which then goes back to the
observation that all wire has a bend in it from the manufacturing process,
and this also causes unlevelness.   I don't know how that could be proven,
since the wire is elastic and the tension seems that it would pull this
wire "straight" And even if proven, can correcting the out of levelness
from this cause give an appreciable improvement in tone?.  After all that
seems to be the objective of leveling strings. 
	Now some claim to produce an audible result from leveling strings. That
is the emperical part. And that is ultimately (finally) determined by
consensus. A group of technicians gather around a piano and so and so
bends a wire and the consensus is "Yes we hear an appreciable improvement
in tone." The true technician though must ask, will this last, and/or will
it cause something detrimental to emerge? And there might be some one
present that who would say, "I hear those noises all the time, but I have
always voiced to eleminate them", and so demonstrate.   
	Anyhow, how interesting it would be at a gathering of technicians, to
listen to a piano, and have the advocates of string leveling by ear point
out a string sounds to be a candidate for leveling, demonstrate that it is
indeed unlevel, level it, demonstrate that it is indeed level, had have
agreement that an appreciable improvement was made. 

Richard Moody