Maximum tension

[Newton Hunt]

You don't want much do you?  (sigh)

There are two ways to think about the issue of what is
best.  Some like to go for a high power concept of scaling
and other like to balance tension and inharmonicity.  I am
of the later school.  There are some scales where the string
length precludes "ideal" values but we can come closer to
that ideal by increasing the number of wound strings in the
middle section and not allowing either tension or
inharmonicity to control but allow both to balance as
closely as possible.  You are right, too low or two high of
either will not tune or sound well.  I am not sure that
aluminum is a real answer but I have not worked with the
material to know any different.

On some pianos scaling is an exercise in frustration because
we are constrained by the speaking lengths unless we are
willing to relocate or redesign the bridges, which most
folks are not willing to do.  So we do what can be done and
hope the minor improvements or changes don't cloud the
broth.

If you take the measurements and look at the graphs of
what's there compared to "optimum" curves you will get an
idea of how far off some factories were and how much it is
possible to improve the sound of the piano by some judicious
choices.

I don't claim to know all there is about scaling, far, far
from it, but I do like what I have done to some pianos and
others who have asked me to do a scale for them have also
liked what I have done.  So I go on with what I have found
to work for me.

This is not an exact science but one does develop a feel for
what can and what cannot be done for a particular piano.

The reason I got into this is because very often the strings
I took off an old piano sounded better than the new ones I
put on.  I hated this but observed that the copper was
shorter on the new strings than on the old strings and then
came along bass scale formulas and computers.  So what was
happening was the string winders were changing the scales
without understanding what they were doing.  I asked one why
and he said he didn't know but that is the way they had been
doing it for  years.  Now I send the string winder a set of
specifications.  Use this core, this copper, start here and
end there.  That way I get what _I_ want and not what they
want to give me.  Doing it this way I have found that I get
outstanding results and any errors are mine, not theirs. 
What has happened but that is another story.

Yes, a badly set up scale can be untunable and yes, it can
be improved AND I don't need what is or was there to make a
good scale although I do like to know what was there just so
I can gloat over my changes.

Does that help?

		Newton

Richard Moody wrote:
> 
> ----- Original Message -----
> From: Newton Hunt <nhunt@jagat.com>
> To: <pianotech@ptg.org>
> Sent: Thursday, June 08, 2000 8:23 AM
> Subject: Re: Maximum tension
> 
> > The discussion now is about wound strings in the middle
> > section.  Ric is correct, wire size is important here BUT
> > the real problem is excessive tension because of too large a
> > wrap.  Also inharmonicity is extremely high.
> >
> > So rescaling is essential for durability.
> >
> > Newton
> 
> Which may explain Everett's thinking in using aluminum wrap in these
> "cross-over" strings.  Anyhow fwiw, the inharmonity formula predicts that Ih
> is less as tension goes up.
>     Don't ask me why,  its just a hunch,  but I  think a string would
> exhibit less inharmonicity at its "optimum elasticity level."  Since piano
> wire is elastic there must be an "ideal  tension."   As the tension goes up
> it approaches the elasticity limit, and the dogma dictates you don't want to
> go over that. However the  elasticity limit is well below the breaking
> point, and some pianos might have strings over the elasticity limit.
>     Two low of tension the string doesn't sound right.  Too high tension, it
> breaks before too long.  What is the happy medium?   The tone has to be
> pleasing and the harmonics close.  Nothing is more fustrating than an
> octave  whose second and first partials are in tune, but the fourth and
> second beat.   I have a piano with such a problem and am hoping a cam-corder
> will record these tuning difficulties. Because if you heard it right after
> it was tuned
> you would say, "Hey, that tuner needs a machine". Like wise if it were tuned
> by machine I am sure the same comments would occur upon aural
> checks.  This piano was re-scaled, (by your's truly) but sounds like it
> needs to be rescaled again. It could have been the bass string order got
> messed up but without the old strings (I had those copied, I did not rescale
> them)  I don't know how I would ever figure that one out.   ---ric