Duo-Art Levels
By Spencer Chase
Pete Knobloch wrote regarding the chart for his loud duo-art. I don't think that an accompaniment level of 20 wci is very loud for level 15 but the lower levels might be what cause it to seem loud. It is the low end (4 to 10 wci) that gives sensitivity to a reproducing piano. You first mention a 0 level of 4.5 wci but later change it to 5 wci. This is actually a big difference for the zero level. Will the piano play without dropping notes at 4 or 4.5 wci? The levels you list in this range are high and could be even higher if the gauge is inaccurate. If it is a cheap (less than $300 new) modern gauge it could be way off. The only way to get meaningful vacuum figures is with a water column or with a gauge callibrated with a water column. I don't like to hook up a water gauge (even with a trap) to a piano since I can be somewhat klutzy now and then. I have a few very good gauges which I check against a water column once in a while and they are always very close. For the low end I use a 0 to 10 wci gauge. There might be some way that your dynamic (while playing a roll) levels are higher than the static (tested ones), but I can't think of anything that would cause this. Craig? Dynamic levels on a duo-art are lower due the lack of a regulator. If you need to change the accordian spacing as much as you did to get 20 wci at 15 there is definitely something wrong with the expression box like leaking knife valves (which are probably sticking too.) The need to make any radical changes from factory settings on a duo-art indicates that something is wrong. Duo-arts are hard to patch together since everything is so interdependant. You probably need to rebuild the stack and expression box if they haven't been done properly in a long time. They way the duo-art attains the required playing levels is very dependent on the stack valves leaking the right amount at the right time. The coding is heavily weighted for chord size and natural playing will never happen if this isn't right. Unfortunately the cross valves together with modern leather are a bad combination. One other thing to be careful about. Make sure that you retain the binary relationship between the accordian spacings or the dynamic (loudness) curve can get strange. I didn't plot your curve but it does look a little steep in the beginning and flat on top. I don't see the exponential increase you previously mentioned, I guess that was before the changes.
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(Message sent Sun 25 Aug 1996, 08:33:28 GMT, from time zone GMT-0700.) |
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