This movie illustrates the interferences between two synchronous pulsating spheres:

• Fluid is air at ambiant conditions  (c=344 m/s)
• Frequency is 1000 Hz
• Source diameter is 10 cm; one source is at (x,y)=(0,0) and the other at (x,y)=(1,1)
• Maximum positive pressure is blue, and minimum (negative) pressure is red
• zero pressure is blue/green (the B&K color!)

The movie was created using MATLAB (Registered Trademark).