> All these emails seem to misrepresent the intentions of the writers. Let's > start afresh. I am very happy with the response you gave me. It showed me > I > didn't understand all of the physics involved. Flexing of the top by means > of fluctuating energy imparted by the string to the bridge. Very good. > Here > the direction of the attack of the string doesn't matter. Very clear. > That's > the sustain part of the sound, I suppose.
Thank you, David. At least this one is cleared. > But Paul's experiment, and many > players' experiences, show that the angle of plucking does influence the > sound. I've no idea what other player's experiences or experiments were like, so can't comment on those. Unfortunately Paul's experiment doesn't involve plucking as such and so, in my view, is rather irrelevant to this discussion. In his own words: (quote) Don't play like you're used to. Just try to make the string move parallel to the soundboard. You can do it by pulling it sideways with two fingers (one over, one under the string) and releasing it. If you got it right, you'll hear almost NO sound, despite quite formidable string movement ... (end of quote). What I realise from this description is that it doesn't even presupposes quick release of the string to provide it with the necessary impulse of energy after it's pulled sideways. And wouldn't the effect be the same if the pulling is made in the upward direction? As Jim pointed out earlier, "the stroke itself must be quick". If we want to carry out a successful experiment in order to investigate which way of plucking is more favourable we've got to actually imitate plucking, not trying to 'fake' it. And with this in mind lets move further. > Why? Is it the attack of the sound we influence? And how? On an > instrument with a bridge on which the strings rest (guitar) I imagine the > string to 'bounce' on the bridge, giving lots of energy through the bridge > to the top. Parallel vibrations just make the string 'slide' over that > bridge. My imagination, I know, but what of it? A parallel plucking motion > gives almost no volume. Then what about all the fluctuating and flexing > going on? Is the attack needed to set the bridge in motion? Cannot imagne > that, somehow. What I think is happening here is this: when the plucking force (or at least some part of it) is directed towards the soundboard , the initial impulse of pressure transmits via the string to the bridge and causes it to tilt forward, thus initiating its 'favourable' rocking movement (from back to front). The degree of this initial displacement would be comparably far greater in the direction perpendicular to the soundboard surface (because of the greater flexibility of the soundboard / bridge structure in this direction) than parallel to it. So this greater initial, as you say, "attack needed to set the bridge in motion" is what indeed may help to 'kick off' the sound, subsequently making it fuller, louder etc. Alexander To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
