Changing Harmonicity

[Bernhard Stopper]

I agree with Ron O.

One should not confuse "Harmonicity" (what is not defined as a physical
parameter) with Inharmonicity.
Inharmonicity is definded as the offset of the harmonics by the effects of
the stiffness of the string and is therefore not dependent of the hammer. It
has nothing to do how "harmonic" impression that different hammers produce
by enforcing or damping different partials.

Bernhard Stopper



----- Original Message ----- 
From: "gordon stelter" <lclgcnp@yahoo.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Thursday, March 04, 2004 4:19 AM
Subject: Re: Changing Harmonicity


> Makes sense to me. The increased hammer weight
> increases the hammer's inertia, making it slower to
> rebound from the string. During that millisecond of
> increased string contact, the smaller segment
> vibrations imparted to the string, which create the
> higher harmonic partials, are somewhat damped by the
> effect of the pressing hammer felt.
>      ( Thump's Theorem #2 )
>
> --- Richard Brekne <Richard.Brekne@grieg.uib.no>
> wrote:
> > Overs Pianos wrote:
> > >>  > One of those other parameters is Hammer
> > Weight.  It has been
> > >> reported to
> > >> me
> > >>
> > >>>  by Vince Mrykalo that increasing the hammer
> > weight reduces
> > >>> inharmonicity
> > >>>  significantly....
> > >>
> > >>
> > >> How?  By diminishing the influence of higher
> > (more inharmonic) partials??
> > >
> > >
> > > At 11:59 AM -0500 3/3/04, Sarah Fox wrote:
> > >
> > >>
> > >> I don't see how the properties of an impulse
> > delivered to a resonant
> > >> system
> > >> can alter the resonant frequencies of that
> > system.
> > >
> > >
> > > Neither can I. The four known factors which
> > determine inharmonicity are
> > > wire stiffness (including that of the wrap wire in
> > the bass), string
> > > tension, the shape of the string termination and
> > the length of free
> > > string segment on the other side of the speaking
> > length termination (ie.
> > > the duplex or counter-bearing string segment).
> > >
> > > Ron O.
> >
> > Well... in defence of David... I seem to remember a
> > thread a couple
> > years back  that got into how hammer hardness
> > affected inharmonicity as
> > measured by RCT.
> >
> > But even if that is true... I dont see how one can
> > isolate hammer weight
> > from factors like density and resiliancy to get at
> > any quantifiable way
> > of determining its effect on inharmonicity.
> >
> > As far as factors that determine inharmonicity are
> > concerned... I also
> > seem to remember reading in one of the physics
> > articles I've collected
> > these past couple years that pianostring
> > inharnmonicity is can indeed be
> > somewhat affected by the condition of the exciting
> > force... something
> > about the strength of any given excited partial
> > having some impact on
> > the frequencies of others.... I'll have to dig
> > through what I have and
> > see if I can find that... but I think the point was
> > that tension,
> > length, termination condition, and not speaking
> > segments are static
> > values that dont take into consideration the
> > dynamics of an excited
> > string, or underwhat conditions it was excited.... I
> > am admitedly a bit
> > foggy on this one so I reserve the right to be too
> > far out on a limb on
> > this one.. grin..
> >
> > Cheers
> > RicB
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > pianotech list info:
> https://www.moypiano.com/resources/#archives
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Search - Find what you're looking for faster
> http://search.yahoo.com
> _______________________________________________
> pianotech list info: https://www.moypiano.com/resources/#archives