Ron wrote: <So tell me, what's so wrong with the current bridge pinning and notching system, if done well, that is inferior to agraffes? Right...my mention of agraffes at all, was in regards to solving a very specific problem raised by Terry's unfortunate encounter with this nasty Steck. That is, looking for strategies that might put a little more distance between the rim and the high bass foot. Thinking out loud zero bearing might allow the use of a cantilever, but then you'd buy engineering tradeoffs that the cantilever brings with it...just trading one badness for another. It doesn't seem like the calculus works out. This Steck thread gets me thinking about the region of the board that is important to the high bass. From what I've seen so far, freeing the panel area behind the high bass or creating a high bass float(as differentiated from the area behind the low bass as in a low bass float) really does not in and of itself effect the nasality of the high bass at all. This leads me to consider several points(questions): 1- the region of the board that is important to the high bass is a rough circumference around the entire bichord area of the bass, not just behind the high bass. 2-mobility (or restriction) is a different quantity than the relative stiffness built into the ribs Terry wrote: <Just strictly considering numerous ribs creating a "hub" of rib origins - and hence making things more stiff than desirable, why not just plane those ribs down (or in two dimensions) at the hub end (so the total cross-sectional rib area is lowered to something more desirable)? My sense Terry is that you are suggesting adjusting relative stiffness of the rib assembly, when the issue is the mobility, not the stiffness. (Terry...I'm still trying to get a grasp on this, so the previous sentence is more a question than a statement) These questions all center around amplitude requirements of this register, or at least "amplitude" as a word I've seen it discussed in these archives. However, the concept of amplitude is where my understanding of the physics gets mushy. It might help if someone could explain what exactly the word "amplitude" is referring to when soundboard mobility is discussed. My understanding (admittedly limited) is that amplitude refers to intensity of sound...maybe volume. Large excursions of the soundboard, ie a large amplitude, would be required to create a loud sound. Frequency requirements are not necessarily large or small excursions, but rather the ability of the soundboard system to allow an appropriate # of oscillations...no? Or put another way, power requires amplitude, the aforementioned "nasality" requires adequate conditions to allow the soundboard to oscillate at an appropiate rate, somewhere close to high bass averaged fundamental frequencies?? Jim Ialeggio -- Jim Ialeggio jim at grandpianosolutions.com 978 425-9026 Shirley Center, MA
This PTG archive page provided courtesy of Moy Piano Service, LLC