Hi David, I once did a rough calculation regarding the contribution of the key stick to the total inertia and came up with a figure of around 18% for the particular action and note I was studying. It then occurred to me that we usually study the action as the key is being pressed down. I think however that the effect of the key stick inertia is more prominent when the key is returning to it’s rest position. That’s when the lever system of the action is decoupled or disconnected, so to speak, and the key stick assumes a much larger proportion of the total inertia. This in turn is noticed by the player who may either feel that the key is too slow to come back up and so the action is never quite ready for the next note, or in the opposite case, that the key is following the fingers up too fast, sometimes pushing them up. Players seem to show a wide range of tastes in this matter, so there is no universally ideal set-up. One other thought, regarding inertia when the key is on its way down. The inertia increases roughly with the square of the action ratio, but linearly with the strike weight. Therefore, I think it will be hard to find truly equivalent combinations of FW and SW, even if we set aside the key dip question and regulation limits. I do however often ponder the effect of the trade-off between high and low SW with the corresponding adjustments in the action ratio. Some would say that the SW must be matched to the string tension and scale, and the rest follows from that. Vladan
This PTG archive page provided courtesy of Moy Piano Service, LLC