changing harmonicity

[gordon stelter]

Yes, and the further up the harmonic sequence we go,
the further from the theoretical termination points
for string vibration do the vibrating segments shrink,
due to wire stiffness, causing the upper harmonics to
swerve radically askew from the ideal, creating
harshness. Which is why so many small pianos sound so
yucky: heavy gauge wires pulled to higher tensions, in
an effort to excite an inadequately sized soundboard =
excessive stiffness = wildly askew harmonics.
     Combine that with hard hammers ( which favor the
upper partials ) and you get the utterly delightful
"BanjoTone" of which I am so very, very fond.
     Thump

--- Overs Pianos <sec@overspianos.com.au> wrote:
> Joe, Richard et al,
> 
> At 7:47 PM +0100 5/3/04, Richard Brekne wrote:
> 
> >Actually... unless I am mistaken again.. tension
> works in to this 
> >only indirectly, in as much as it is the stiffness
> factor we are 
> >after here. More tension yeilds higher stiffness
> all other things 
> >being equal.
> 
> As Joe rightly claimed, tension affects
> inharmonicity in a very 
> direct way. After all, it is the stiffness of the
> wire which causes 
> inharmonicity in the first instance. If you think of
> a speaking 
> length string segment at the moment during the cycle
> when it is 
> farthest from its resting position (ie. at 90 and
> 270 degrees), if 
> the string did not have some quantifiable stiffness,
> the speaking 
> length would flex right up to the string length
> termination. But this 
> doesn't happen in a real-world piano. Due to the
> wire's stiffness, 
> there is some reluctance on the part of the wire to
> deflect right to 
> the end terminations. Consider the situation further
> as it exists at 
> the termination. On the speaking length side of the
> termination the 
> speaking length is trying to pull the 'reluctant
> string zone' 
> (adjacent to the termination) along with its own
> excursions from 
> rest, while the duplex or counter-bearing segment
> (on the other side 
> of the termination) is trying to hold the 'reluctant
> string zone' 
> steady. Both will have influence so there is certain
> to be some loss 
> of string activity at the speaking length zone near
> the termination. 
> The stiffer the wire the greater the effect, the
> higher the tension 
> the less the effect. The higher tension will force
> more of the 
> 'reluctant string zone', adjacent to the
> terminations, to be active.
> 
> So while a higher string tension increases the
> string's ability to 
> resist the blow of the hammer, it also forces a
> higher percentage of 
> the speaking length segment to be active, lowering
> inharmonicity.
> 
> Ron O.
> -- 
> OVERS PIANOS - SYDNEY
>     Grand Piano Manufacturers
> _______________________
> 
> Web http://overspianos.com.au
> mailto:info@overspianos.com.au
> _______________________


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