Actually, part of what you wrote is quite close to what I think is happening. When the pulse from the string hits the bridge and therefore the soundboard, it travels in the board until it gets to a place on the board that no longer can move because it's attached to the rim or something hard. There, the pulse reflects and part of it travels back towards the bridge. If you do it right, that returning wave reinforces a later pulse that is just entering the board at the bridge. Obviously, that distance and the time required for the round trip is a function of the frequency, so the fish has to progressively move away from the bridge as the frequency gets lower. The cut-off serves the same function on the other side of the bridge. My guess would be that the cutoff should be the same distance from the bridge as the rim or fish is on the other side of the bridge, so you get a double effect. So the bridge should follow a path right in the middle between the rim and the cutoff. If the distance is wrong, you get a pulse that returns just in time to cancel the next pulse (or some later pulse), and the impedance of the board will look very wrong. If the distance from the fish or cutoff is too long, you will get some interference and some notes will cancel while others will enhance. Any comments? Vladan ========================================= is that it stiffens this area of the rim so that vibrations travelling from the board are not creating friction, and lost as heat energy ( due to molecular "wiggling" ) but are more likely kicked, or otherwise ransmitted, back into the board. Right ? ( Praise Be to the Circle of Sound! ) Thump __________________________________ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com
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