Pyro Board: 2D Rubens' Tube!
This Rubens' tube visualizes the standing wave pattern of sound through flames. This two-dimensional Ruben's Tube has over 2,500 flames in it that react to standing waves. The video says that "the pressure variations due to the sound waves affect the flow rate of flammable gas from the holes in the Pyro Board and therefore affect the height and colour of flames." When music is played through the speaker the flames move in coordination to the sound. It is quite a visualization of sound!