Abstract: A musical instrument includes a two-dimension array of note producing elements wherein the elements along one dimension of the array have three-quarter steps or increasing fundamental frequencies F.sub.n according to the equationF.sub.n =F.sub.0 *2.sup.n/8wherein F.sub.0 is the fundamental frequency of the first note producing element in the one dimension and n is the number of the note producing element in the one direction from the first note producing element. The note producing elements along a second dimension of the array have fundamental frequencies which differ by frequency differences (such as perfect fourth intervals) greater than the frequency differences between adjacent note producing elements along the one dimension of the array.