free103point9 transmission artists 31 Down recently worked on "Dusk: The Sound of Bats," is a solar powered “bat detector” during their residency at Wave Farm. The installation uses the high frequency radio transmissions of the bats living at Wave Farm as its subject matter. Bats emit sounds via echolocation, at typically two or three times higher pitch than that which the human ear can hear. Using an ultrasonic microphone paired with a customized scanning device, 31 Down will translate the bats' transmissions into audible frequencies. This show will feature bat recordings they made during their residency.