hammer mass (was Wurzen felt)

[David Love]

Correction, that should have read 7/32" shank.

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: David Love <davidlovepianos@earthlink.net>
> To: Pianotech <pianotech@ptg.org>
> Date: 5/12/2003 10:32:06 AM
> Subject: RE: hammer mass (was Wurzen felt)
>
> Yes, it seems that it is not a pure test.  It was interesting, however, to
> observe the difference.   It brings something else to mind, which is what
> happens when, say, a new action with 7/16" shanks is combined with a
hammer
> weight from the original design which utilized 3/16" shanks and of a
> different species of wood.  My own experience does suggest that a light
> hammer on a 3/16" maple shank does not sound the same as that same hammer
> on a hex 7/16" shank made of hornbeam.  
>
> David Love
> davidlovepianos@earthlink.net
>
>
> > [Original Message]
> > From: Stephen Birkett <sbirkett@real.uwaterloo.ca>
> > To: Pianotech <pianotech@ptg.org>; <davidlovepianos@earthlink.net>
> > Date: 5/12/2003 9:18:36 AM
> > Subject: hammer mass (was Wurzen felt)
> >
> > David Love scripsit:
> > >  I have had an experience on the other end fo the spectrum.  I
> > >have a customer with a Hamburg Steinway A (newer one).  She wanted the
> > >action heavier so a previous technician put clips on the shanks. 
Though
> > >she liked the weight, the tone became very unpleasant to her and others
> who
> > >heard the piano.  I suggested we try removing the clips (she had not
made
> > >the connection), fortunately an easy thing to do.  The tone that she
had
> > >loved about the piano returned.  A match of hammer weight to the
> soundboard
> > >assembly (and the relative density of the hammer, perhaps), is clearly
> > >important.  Heavier hammers do not always sound better, as I have often
> > >heard stated here.
> >
> > An interesting experiment, for sure, but putting clips on the shanks 
> > is not the same thing as simply "increasing hammer mass". The clips 
> > will certainly affect the resonsant frequencies of the shanks which 
> > may well have been a significant contributor to the tonal change. We 
> > don't yet have general relationships which connect shank flexibility 
> > to tone, but there's plenty of anecdotal evidence about this, and 
> > shank resonances are a proposed mechanism.
> >
> > How to increase mass without altering shank resonance frequencies? 
> > You can't because *any* change in mass distribution of the 
> > hammer/shank system will influence these. Even adding or removing 
> > mass to (from) the hammer core may influence tone by altering the 
> > strike mass/string relationship, or by altering the shank/hammer 
> > resonances, or both. These are different phenomena. Unfortunately the 
> > nature of piano action mechanism makes it impossible to adjust 
> > independently only the strike mass/string mass relationship [which is 
> > what will be generally understood by "adjust the hammer mass"].
> >
> > Ah...the complexities of our difficult friend the pianoforte.
> >
> > Stephen
> > -- 
> > Dr Stephen Birkett
> > Associate Professor
> > Department of Systems Design Engineering
> > University of Waterloo
> > Waterloo, Ontario
> > Canada N2L 3G1
> >
> > Davis Building Room 2617
> > tel: 519-888-4567 Ext. 3792
> > PianoTech Lab Ext. 7115
> > mailto: sbirkett[at]real.uwaterloo.ca
> > http://real.uwaterloo.ca/~sbirkett
>
>
>
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