---------------------- multipart/mixed attachment Hello Sarah, Ric and Friction Thread, For the sake of keeping the discussion on target, let's assume for a moment that we have no way of finding out what exactly is going on in the pianists body/mind as he tries to control the pressure on the key. To summarize, there are at least three options available: Option 1. The pianist does not have any time to react to his movement once he starts pushing the key down. He is playing "open loop" and acts from some previous knowledge of what might work well. Depending on how well he knows the piano and his skill level, he gets it more or less right. Maybe he is really great and learns very quickly, so after playing a new piano for a short while he figures the instrument out. Option 2. On slow passages, he has enough time to adjust his touch, and that in combination with his general pianistic skill gets him through. On fast passages, there is no time to react and dynamics take the back seat. Option 3. Some combination of the above. Going back to mechanical systems with mass, springiness and friction, I have made a plot of two theoretical scenarios. The plots are attached (I hope they get posted correctly). The plots are pure math, showing two systems which are equal, except for the friction. In other words, the inertia and the springiness are unchanged. This mathematical concept is universal in nature and can be found just about everywhere. The horizontal axis represents time. The vertical axis represents the momentum in the hammer. The red trace represents a system with more friction than the blue trace. I have normalized them so that they coincide in time at about 90% of the final momentum value. This means that both pianos will sound the note at the same time, assuming that the jack releases at about 90% of the available momentum. For the sake of this discussion, that number can be 95% or 99% - I just had to pick a number - it doesn't really matter much. The important thing to notice is that for a constant force on the key, the system with more friction will take more time to get the hammer to the required momentum. It takes about 2.4 units of time for the blue trace to go from 10% to 90%, but it takes about 3.5 units of time for the red (higher friction) trace. Back to the issue of control: Up to a point, if the musician has more time to push the key (for a given required momentum), he will probably be in more control. If there is too much friction, things will not be so pleasant, as he will have to push harder, or else he will run out of time. If the action has less friction, he will have to be more nimble - there will not be much time between the pressing and the releasing. Also note that the piano with the higher friction will require the pianist to start with the note just a little sooner so that the note can sound on time; in a sense he too has to be fast. It's just that on the higher friction piano he has to be faster moving his hands/fingers between notes. I think that this is fundamentally the first order effect we are discussing. It gets more complicated, of course, but I hope the description sheds some light! Vladan _______________________________ Do you Yahoo!? Win 1 of 4,000 free domain names from Yahoo! Enter now. http://promotions.yahoo.com/goldrush ---------------------- multipart/mixed attachment A non-text attachment was scrubbed... Name: response.jpg Type: image/jpeg Size: 70476 bytes Desc: response.jpg Url : https://www.moypiano.com/ptg/pianotech.php/attachments/63/b0/f1/01/response.jpg ---------------------- multipart/mixed attachment--
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