Imagine searching for a gemstone in a dark cave: You use a flashlight, looking for a rainbow-colored glint in the darkness. Now, imagine 10 other people in the cave with you, using different-colored flashlights at the same time. Suddenly, you can no longer tell which light is coming from your gemsto ne, which light is from another flashlight or which light is coming from a reflection off another unknown object. That is what echolocation with multiple, overlapping frequencies would be like. But now, imagine if every person in the cave were using a flashlight of the same color. The glint from the gemstone would be much easier to see. ...read more read less