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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