A group of interdisciplinary researchers are studying whistles, flutes, and other noisemakers found at pre-Columbian sites in South Central America. For example, archaeologists exploring an Aztec temple discovered a human skeleton holding an unusual skull-shaped whistle in each hand. The researchers dubbed the instrument's wail, the "Whistle of Death." The Associated Press has an article on the topic of pre-Columbian noisemakers including sound samples (snip of photo by Alexandre Meneghini):
The Aztecs sounded the low, foghorn hum of conch shells at the start of ceremonies and possibly during wars to communicate strategies. Hunters likely used animal-shaped ocarinas to produce throaty grunts that lured deer.
The modern-day archaeologists who came up with the term Whistles of Death believe they were meant to help the deceased journey into the underworld, while tribes are said to have emitted terrifying sounds to fend off enemies, much like high-tech crowd-control devices available today.
Experts also believe pre-Columbian tribes used some of the instruments to send the human brain into a dream state and treat certain illnesses. The ancient whistles could guide research into how rhythmic sounds alter heart rates and states of consciousness.
Pre-Columbian sounds (Associated Press)