<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body bgcolor="#FFFFFF"> David Love wrote: <blockquote TYPE=CITE><style></style> 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.</blockquote> This is the heart of Ed McMorrows thinking. He would also add that friction is quite reduced with lower hammer weights, though he does not formally work this into his equation.  However, while F=m*a is quite simple in itself and has led Ed and others to believe that the mass reduction of a lighter hammer can be sufficiently compensated for by increased acceleration, many years experience with this approach has not born that claim out. One need do no more complicated experiment then to take a hammer from key 88 and lead it to the same weight as key 1 and exchange the two to begin confirming that things are not so simple. Voice all you want, or use different hammers all you want, and there is still a difference in sound. Perhaps its as simple as saying velocity simply does not compensate for mass in the sense we seem to assume here.   <blockquote TYPE=CITE>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.</blockquote> Thats an interesting claim, tho I dont see it qualified in any sense. And I have heard the opposite being stated, equally unqualified I might add. I wonder if you might try and justify all this a bit in terms of the mechanics involved. Just why do you think a more massive hammer effects no change (or a negative one perhaps) at pppp ? And how can you show that a light hammer can be more reliably controlled ? very curioius. <blockquote TYPE=CITE>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.</blockquote> I dont think it has been shown that hammer rebound from the string is mostly a function of its mass. Rather I think it has been shown that the hammers resiliancy has the most determinant function in this regard. Neither do I understand that a lighter hammer allows any particular greater freedom in terms of key dip, or blow. These parameters vary quite enough as a matter of course already. We see everything from a little over 9 mm dip to circa 11 mm dip coming out of factories, and from as little as 42 mm blow to as much as 50. There is in fact no standard by which to define what a "compromise of keydip, blow or both" is. Lowering the ratio will make it lighter at the key, and yet it will it will travel less distance with equal key movement, and thus more slowly at equal key speed. But because it seems lighter at the key..... the finger playing will have a tendancy to compensate in order to achieve similiar degrees of sound volume. And its the pianists fingers this is in the end all about. It might be instructive to simply change the ratio and compensate the action regulation with a change in blow. This would keep key dip and hammer mass constant in an attempt to better identify the effect of a change in ratio on the perception of touch. <blockquote TYPE=CITE> Those are my thoughts.  Feel free to comment.David Love</blockquote>  me too :) -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway <A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A> <A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A>   </body> </html>