Del, Ron N. and others Ok.. let me see if I understand this correctly so far. If we are going to try and match strings to the soundboard impedance, we first have to undestand a few things about soundboards. In the most general of terms this means understanding how soundboard stiffness relates to sustain, and how soundboard reasonant frequencies can be manipulated. My reading so far tells me that in a stiff soundboard, the lowest resonate frequencies (those under 500Hz) of the soundboard will be higher and the peaks and valleys of those resonances will be less defined then a less stiff soundboard. The less defined those resonances are, the fewer problems incured with string frequencies that coincide with those, being sucked up by the board (ie, no sustain at board resonances) Since there is an upper limit with regards to the stiffness of the board (because too much sustain is also = to thin crashy sound ?) we are left with a trade off situation. We can effect change in these resonance frequencies by increasing or decreasing stiffness to the board by 1: increasing / decreasing the height of the ribs, particularily in the middel area of the board. 2: increasing / decreasing the height of the bridge. 3: increasing / decreasing the downward pressure exerted by the strings on the bridge 4: adding / subtracting mass at various points on the board. 5: changing the tension of the strings. (anything else ?) The basic idea is to create a situation where the board is in general stiff enough to radiate sound adequatly, and at the same time manipulate the resonate frequencies so that they (as much as posible) do not coincide with string frequencies at concert pitch ?? And at the same time incorporate a stringing scale with decent inharmonicity characteristics ?? I realize that this is just a begining and far from complete, but are there any mistakes in my understanding so far ?? A couple questions here.. what is meant by the "phase angle" of the impedance and how is this (if it is at all) manipulated. And secondly, I am wondering if these resonant frequencies can have anything at all to do with this buisness of para inharmonicity. Strikes me as odd that negative inharmonicity is found primarilly in the area under 500 Hz and only then at a few (non adjacent ??) strings, which is the same area where these resonanances are of most concern. I may be jumping to conclusions there but it does strike me as a posibility. Please inform where my understanding thusfar is lacking / directly wrong, etc. Richard Brekne I.C.P.T.G. N.P.T.F. Bergen, Norway
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