the individual projection portion 18 in fig5 indicates an empty space which corresponds to empty space 21 of fig2 as can be seen from fig5 each half of a row includes eleven elements and one blank or empty space wherein the rightmost half row includes the space 18 while the leftmost portion of the row which is shown in fig2 includes the space 21 as discussed above the cavities formed in the sound diffusor 10 create a structure capable of diffusing sound of various frequencies fig6 drawn to scale is a schematic top elevational view of a half section of the diffusor 10 of fig1 showing the angle of inclination of each projection as can be seen in fig6 rows 30 alternate with rows 40 these rows being staggered by one space which is equivalent to the width of a projection as discussed above in reversing a row 30 to form a row 40 the rotation can be conceived of as being about an axis which is perpendicular to the plane of fig6 as a result a three dimensional pattern is formed for the diffusor 10 which is capable of diffusing sound in both the horizontal and vertical directions a second section of the device positioned to the right or left of fig6 would be a portion corresponding to the rightmost portion of row 30 i e that portion which is to the right of the empty space 21 this is discussed more clearly below the sound diffusor 10 is preferably composed of two of the units shown in fig6 as schematically shown in fig1 the dimensions of diffusor 10 as shown in fig1 are approximately thirty inches by thirty inches by nine and one half inches assuming the base 11 has a thickness of one half inch of course.