<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> Ok gang, Arthur Benades book "Fundamentals of Musical Acoustics" at the end of Chapter six he make a short dip into the natural vibrations of extended objects and his example for this is very similar to our pond example. Instead he is using a Trough of Water in which the water is caused to slosh back and forth. This is on page 88 - 90 for anyone who has the book. The point is that he ties the vertical component of the waves directly to the horizontal component.  Looking from the side we are still in a 2 dimensional system, but we clearly can see both the transverse and longitudinal components in action at the same time. And the neat part is that, and I quote   <blockquote>"in every case (for each successive mode) the largest horizontal oscillation of the water takes place precisely at those points where the vertical motion is zero. Conversely we find that the nodes of the horizontal motion are located at the exact spots where the water's vertical oscillation is the largest. We have discovered that every mode of watery oscillation in a trough has two interlaced aspects: a vertical motion and a horizontal motion...."  </blockquote> This is still in the opening chapters of his book and I still don't have anything to couple this kind of wave propagation directly to the sound board. But if vibration energy has to propagate in similar fashion for all elastic medium...then ...well I am still pointed in that direction. In any case it was neat to see that my thinking along the pond / ripple tangent wasn't completely out in left field. :)   Ricb       -- Richard Brekne RPT, N.P.T.F. Bergen, Norway <A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A>  </html>