Get Your Science On: Chronophones

This week, McKenna teaches us how to build Chronophones, a classic LSOP experiment that makes things sound like they’re coming from different places than they actually are.

What’s Going On

One way your brain can tell where sound is coming from is that it uses timing information. If someone is standing on your left, their voice will get to your left ear first, before it gets to your right ear. Your brain can use the amount of time it takes between when sound arrives at one ear and when it arrives at the other to infer the location of the speaker.
Chronophoes makes all the sound go through tubes to get to your ears; however one tube is longer than the other, so it takes sound longer to get to that ear, and your brain thinks the sound must be on the opposite side.

Materials

  • A pair of safety ear muffs
  • Flexible tubing
  • A funnel
  • A PVC tee joint
  • Lots of tape or glue to hold it all together.
  • An electric drill

How to Build It

Cut the tubes to length. We made one tube approximately 20cm longer than the other. Drill a hole in each ear muff, and insert one tube in each. Insert the other end of each tube into the opposite sides of the PVC tee joint. Attach the funnel to the perpendicular side of the PVC tee. Hold everything together with glue or tape.