For you gear junkies, this is no new invention. The octobasse (dubbed "octobass") is a stringed instrument hailing form 1850 by French instrument maker Jean-Baptiste Vuillaume. Requiring a heavy-handed player, the instrument is capable of producing a sound humans are incapable of hearing.
Sure, it's low but how low? As So Bad So Good points out, it's tuned two octaves below a cello, with its lowest C note emitting a frequency at 16 Hz. And if you were wondering, yes, it's too low for the naked ear.
The article continues:
"The strings are so massive that the vibrations are slow enough for us to see them. Which is a great visual for people to understand what's happening when we drag the bow across the strings."
With only two legitimate octobasses to date, there is a quite passable replica at the Musical Instrument Museum in Phoenix, Arizona, where curator Colin Pearson demonstrated the use of the behemoth.