PianoDisc solenoid placement?
By Roger Stern
For anyone familiar with PianoDisc installations, what are your thoughts regarding solenoid strike point on the keys? The PianoDisc installation manual says the optimum point is right under the capstans. However, there are other inferences in the PianoDisc documentation that say the strike point should be as far back on the key as possible. As you move the strike point back on the key, the solenoid throw clearance, and the solenoid leverage, increases due to the geometry of the situation.
It will be several months before I have a test system set up and have an opportunity to run some experiments, but it seems that the optimum solenoid strike point may actually vary from from one instrument to another. It looks like the PianoDisc solenoid throw range is about 1/2 inch. The Grand actions I am familiar with have a full dip clearance near the back of the keys of about 7/16". Uprights seem to be more like 5/16", with only about 1/4" full dip clearance at the capstan location.
Different actions seem to have different loading (touchweight) characteristics. The solenoids are probably designed to provide a loaded stroke that simulates a human keystroke when a current pulse of the correct shape and duration is received. Getting these two things together in the right way probably has a lot to do with how well the systems perform in any specific instrument. I suspect PianoDisc has some drive current "pulse shape" adjustment capability built into their electronics to allow for differences in keyframe geometry and action loading ... but it also seems that the strike point of the solenoids on the keys would have a lot to do with how well the units perform. Does anyone have any experience in this area they would be willing to share?
Roger Stern on Bainbridge Island, Washington State.
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(Message sent Wed 1 Nov 1995, 01:24:19 GMT, from time zone GMT-0800.) |
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