To be or not to be: a heavy hammer

[Isaac OLEG]

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While I tend to believe that concert instruments will benefit of hammers in
the "high" zone of the chart, I see that the flexing of the shank add
velocity to the hammer too.

Lighter hammers tend to produce a cleaner sound , but my impression, because
of the so large mass of every other part of the piano, is that they will
give less low partials, as noticed on the re felted hammers I meet sometime.

It is just a choice in the wanted tone I guess.

To have the Glengould tone we will not need heavy hammers at all, but Arthur
Rubinstein would be sad of a too light one I guess.

Then it is also a board question if I understand well, but I am still to
hear the boards made by certain builders. If CD are available I'd be
interested.

S&S hammers are going on a lighter side actually, but I believe these are
economic reasons too unfortunately (predict wear in 10years).

I'll think of it

regards.

Isaac O..

  -----Message d'origine-----
  De : pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]De la
part de David Love
  Envoyé : jeudi 3 octobre 2002 07:26
  À : Pianotech
  Objet : To be or not to be: a heavy hammer


  The question was put to me off list about why I reject the idea that
heavier hammers are necessary on a concert instrument.  I thought I would
put my reply on list because I think it is an interesting discussion.

  The practice of putting heavier hammers on a concert instrument comes from
the idea that more mass will produce greater force and therefore greater
volume of tone.  But mass is only part of the equation.  Force = mass x
acceleration.  While it is true that if hammers of varying weights are
accelerated equally, the one with more mass will have more force, it is also
true that a hammer of lower mass will be accelerated to a higher velocity
more easily.  This is especially true in a piano where lower mass in the
hammer results in lower inertia at the hammer end as well as in the key.
Whether you have more mass and less acceleration or more acceleration and
less mass, as long as the mass of the lighter hammer is not so much less
that its deficiency cannot be compensated for by increased acceleration, the
potential force in the two examples can be equal.

  Because pianos are played from pppp to ffff, the only area of concern is
in the potential force at the highest end.  You don't benefit from a more
massive hammer at the pppp level.  In fact, since there is a point below
which soft playing cannot be reliably controlled, a lighter hammer will give
greater dynamic range at the bottom end.  So the only concern is at the top
end.  Assuming that the difference in hammer weight can be compensated for
by greater acceleration, the heavier hammer will actually have a narrower
dynamic range.

  As I already mentioned,  a lighter hammer will reap benefits in terms of
lower inertia both due to lower hammer weight and lower front weight of the
keys.  Lighter hammers will rebound off the strings more quickly increasing
sustain and improving clarity.  Lighter hammers will also allow you to
maintain an action ratio that doesn't require compromises of key dip, blow
or both.   One final concern with very heavy hammers is the deflection of
the shank at high level of acceleration.  Though I haven't looked into the
research in any great detail, I know that Renner has given this a lot of
consideration in the design of their shanks.  If, in trying to accelerate a
very heavy hammer to high levels, the shank deflects to the point that the
hammer is striking fairly far from top dead center, how much force and tonal
quality are we losing because of this and, therefore, is there any real
benefit to trying to increase the upper range limit anyway.

  Those are my thoughts.  Feel free to comment.


  David Love

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