Certainly you may. It’s an interesting problem. I was there today, actually, engaged in a long discussion trying to determine just what the problem is exactly. I didn’t set up the action so I’m going at it based on information he is giving me or that I’ve been able to measure on site. The AR is in the low 5’s measured using my dip/blow tool measuring device. The action regulates with quite deep key dip, around 11 mm, such that I have actually shortened the blow and shallowed the dip by 1 mm to see if what he was responding negatively to wasn’t getting buried down in the keys. While it did help it wasn’t the complete answer. SWs are I think what would be called Medium High note #1 about 12 grams and note 88 around 5.5 grams. Not that high actually, especially considering the low leverage. BW is around 35 grams--pretty light though his complaint is about sense of too much weight, ironically. Friction from my samples is around 10 or 11 grams in the bass and around 8 or 9 in the treble—a fairly narrow spread. FW's appear to be relatively low based on number and placement of leads. After a long discussion with the pianist today I think inertia is not really the problem. My present theory is that the problem is a fly-away action. By that I mean that the keys seem to fall away from the fingers too quickly. Once the stroke is initiated the action accelerates with not enough control and the pianist gets a feeling of being disconnected from the keys. The pianist feels that he loses control and a sense of weight through the stroke. Also, because this fly-away issue controlling pianissimo playing is difficult and must be done with the utmost caution in arm weight (I can tell this myself as a player). Yet there is a sense of resistance that he doesn’t like especially in very rapid passage work. Though it is difficult to know exactly what is going on my current thinking is that because of the fly away tendency there is a natural inclination to be very light with the touch even in rapid passage work instinctively in order to avoid the fly away sensation. This attempt at a very light touch makes it difficult to initiate the stroke sometimes due in part, perhaps, to the highish SW numbers. I am leaning toward an explanation that the action ratio is too low and that for this pianist he might be better served with a higher leverage by virtue of a shorter knuckle hanging and lower strike weights keeping the FWs relatively low and the BW the same. Of course, with an existing action it’s difficult to test this without spending a lot of money. My current suggestion, then, is to hang two octaves of hammers with 16 mm knuckle shanks (I have some old Steinway hammers on shanks taken from some action rebuilds in the shop) with modified strike weights (lower) that will offset the change in ratio and leave the BW the same. Not too hard to calculate this and do a prior set up on the parts. Then I can just swap two octaves and he can test it out. The lower SWs will reduce the power slightly but on this 1920s piano with the original board a that won’t probably be such a bad thing as there are some termination problems anyway that are being exacerbated by the higher SWs. Generally, I see a trend in a lot of action rebuilding which I think has potential problems and that is forcing the action leverage down very low in order to get the most facile, low inertia performance. While this undoubtedly appeals to some pianists it can also create problems and not only with regulation (increased key dip), but I’m also wondering if the sense of fly away isn’t also related to an AR which is too low. It would make sense in terms of shortening the shank radius and the faster rate of change through the stroke (time to review my calculus). Comments? David Love www.davidlovepianos.com From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Nick Gravagne Sent: Tuesday, March 16, 2010 1:54 PM To: pianotech at ptg.org Subject: Re: [pianotech] Action inertia FW versus SW This is an intriguing problem, David. Can you offer any more data? For example, how high are the strike weights? The hammer weights (more or less)? How low is the DW and how high is UW (more or less). You say friction is not a problem, any data? Why do you deduce from the pianist that inertia may be the problem? You say, “The only area that can be responsible for the added inertia are the higher strike weights.” Most likely true, but the whole package needs to be considered as (judging from your history on this list) you already know. How low is the action ratio now? Are you able to supply measurements along with method of measuring? Should the overall AR be low for this action, relatively heavy hammers and (possibly) hammer friction centers just on the verge of being too loose will cause the action to feel uncontrollable, and repetition might suffer. The sense being, that once the key is struck, control of the hammer becomes a guessing game, especially for rapid playing. Can we assume that the action spread, elevations and hammer bore are not in question, or at least not likely seriously so? May we have more? Nick Gravagne, RPT Piano Technicians Guild Member Society Manufacturing Engineers Voice Mail 928-476-4143
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