Horace Greeley wrote: > What's going on in the "dead" area of the > soundboard? What do you mean by the "dead" area of the soundboard? > Does the width of the toe of the board allow > a lot of, or discernable standing wave distortion? What do you mean by the "toe of the board?" > Is the board "bound" between the top of the > bass bridge and the back of the tenor section > of the treble bridge? Please elaborate. > I'm not sure about 6 or 7 seconds.... Adding external weight to the bass bridge will "alter" sustain. If the bridge was too light to begin with it might well improve sustain. If it was already too heavy, it would cause more harm than good. It will change the mass/elasticity ratio and thereby alter the soundboards impedance load to the strings. Impedance is not liner with frequency and so the harmonic structure of the sound envelope will also be altered. Just remember that not all overtones are unpleasant. Which is why most manufacturers do go to at least some effort to make bridges as lightweight as is reasonable. This was the idea behind Harold Conklin's "Tone Extender." This is a brass weight mounted on the back of the soundboard at the end of the tenor bridge. It compensates for the fact that the tenor bridge ends. Hence, both its stiffness and mass change radically from what they were just an octave -- or whatever -- above. (This device was patented and I don't know if that patent is still in effect or not. You'd have to check with the patent office or with Baldwin.) Earlier builders compensated for this effect in various other ways. Usually by simply extending the length of the tenor bridge beyond the last tenor bridge pin set somewhat. Or, in the case of Steinway (and their many emulators), by wrapping the end of the tenor bridge around and hooking it up to the bottom end of the bass bridge. This does wonders for the low tenor, but it doesn't help the low bass much. The factors that go into choosing bridge mass and stiffness are way too complex to go into here. It depends on the structural design of the soundboard and rib set, the distance from the bridge to the inner rim, the speaking length of the scale, the length of the back scale, scale tensions, etc. Fortunately, because of the non-linear nature of impedance, the mass of the bass bridge must be greater than that of the tenor bridge, so the added mass of the taller bass bridge is not generally a problem. It would be unlikely to find a bass bridge with one of those abominable aprons that was too light. It's possible, however, that one of the very lightweight, through-drilled, or "violin-style" bridges might be. If you wish to experiment with this, go to it. Just do it in a way that is reversible. You always want to be able to get yourself out of trouble. -- ddf
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