Long story short: The mysterious sound known as The Hum has been reported worldwide for decades, yet its source remains impossible to find. Researches tested whether people who hear it have exceptional low-frequency hearing or measurable sounds produced inside their ears, but neither explanation fits most subjects. The leading conclusion is that many cases involve low-frequency tinnitus — even though the sound's source appears completely external.Full ScienceDaily story here.More?Dr. Glen MacPhe...