Bag End was recently commissioned to build a custom subwoofer utilizing its Infra technology for elephant field research by Dr. Michael Pardo, a post doctoral research fellow in the Department of Fish, Wildlife and Conservation Biology at Colorado State University for an exploration of vocal communication between African elephants at the Samburu National Reserve in Kenya.
Specifically, he’s investigating the function of vocal learning ability in the wild elephants, including the possibility that elephants call one another by name. One of the elephants’ call types, the “rumble,” is the most common and acoustically variable. Large vocal production anatomy is responsible for the low-frequency of the rumbles, with frequencies in the infrasonic range. Long-distance communication is thought possible because low-frequency sounds degrade more slowly over distance than high-frequency sounds, and elephants respond to rumbles produced more than a mile away.
In addition, experiments have demonstrated that elephants can detect infrasonic tones and discriminate small frequency differences. There’s also evidence that the structural variation in rumbles reflects the individual identity, reproductive state, and emotional state of callers.
It’s challenging for the loudspeaker system to reproduce not only the low-frequency spectrum but clarity and detail in a range below human hearing. Bag End states that the time domain accuracy of its Infra system helps provide a more realistic acoustical environment to the elephants, thereby improving the accuracy of research.
