Ruben's tube

I saw this on a tour of Lancaster University Physics labs last year. Gas is fed into a tube with a series of holes along the top. The gas escaping from the holes is lit. There is a loudspeaker at one end of the tube and music is played into the speaker. Sound is a series of pressure waves - compressions where the pressure is higher and rarefactions where the pressure is lower. So where the sound wave is at higher pressure the flame is taller because more gas is forced out. Rarefactions produce shorter waves. So the flames go up and down in time to the music. I want one!