>To those of you who use wippens with assist springs, > >1. Do you adjust them so that they are giving the same assist on every key? In other words so that WW (wippen weight) is the same for every key? Or do you adjust them so that the assist is tapering from more in the bass to less (or none) in the treble? > >2. In my opinion, actions with strong spring assist don't feel 'normal'. What do you think is the limit of spring assist at which the action might still have a normal feel? > >3. How you measure the amount of assist that you're getting? > >Phil Ford Hi Phil, I'll answer your questions in reverse order... The easiest way to measure the amount of assist is to measure up weight then disengage the spring and remeasure up weight again. You can use down weight if you prefer. Up and Down Wt will both rise by the same amout when the spring is disengaged. (springs don't effect the friction significantly) For instance: if you have a key that is 20/50 and with the spring off is 28/58 then the spring is working 8 grams. As a general rule it's safe to work the springs so that they just support the weigh of the wippen. This would take about 9-11 grams off the touch weight. 17 grams is generally considered the upper limit to working springs without significant risk of comprimising normal feel. Some pianists are more sensitive to the effect than others. How much the spring can work depends on the diameter of the spring. Renner makes three sizes, 0.7mm, 0.6mm, and 0.55mm. If you are going to work as much as 17 gram off the down/up wt then use the 0.7mm, for up to 12 grams use the 0.6mm, and for up to 6 grams use the 0.55mm spring. Perhaps the easiest way to use wippen support springs is to adjust the tension of 88 springs with the stack on the bench so that it lifts the wippen almost to the drop screw. This makes the WW essentially zero. Once the tension is even on all the springs then weigh off your keys to a normal down weight (assuming friction is even) or a specified balance weight. This is the method that Steinway Hamburg used for a time in the 20's. If you end up back leading in the treble you can taper the spring tension down to zero in the last octave. You can also taper the spring tension from Bass to Treble with the springs ending at any point you want. I prefer using 88 springs with uniform tension throughmost of the keys with a tapering off of tension in the last octave. Springs should be considered as a high performance option, not a fix for mismatched hammer weight/ratio. David Stanwood
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