Calculations: fres = c/2 * sqrt( (l/lx)^2 + (m/mx)^2 + (n/nx)^2
), with l,m,n = 0,1,2... and c as sound velocity
main modes: one wall, secondary modes: two walls, not considered: all
3 walls
*) at 20 Grad centigrade, calculation according to American
Institute of Physics Handbook, 1957 McGraw Hill, Inc. |