Nov 22, 2010

3,000-Year-Old Trumpet Played Again

Now you can hear a marine-inspired melody from before the time of the Little Mermaid's hot crustacean band. Acoustic scientists put their lips to ancient conch shells to figure out how humans used these trumpets 3,000 years ago. The well-preserved, ornately decorated shells found at a pre-Inca religious site in Peru offered researchers a rare opportunity to jam on primeval instruments.

The music, powerfully haunting and droning, could have been used in religious ceremonies, the scientists say. The team reported their analysis Nov. 17 at the Second Pan-American/Iberian Meeting on Acoustics in Cancun, Mexico.

"You can really feel it in your chest," says Jonathan Abel, an acoustician at Stanford University's Center for Computer Research in Music and Acoustics. "It has a rough texture like a tonal animal roar."

Archaeologists had unearthed 20 complete Strombus galeatus marine shell trumpets in 2001 at Chavín de Huántar, an ancient ceremonial center in the Andes. Polished, painted and etched with symbols, the shells had well-formed mouthpieces and distinct V-shaped cuts. The cuts may have been used as a rest for the player's thumb, says study co-author Perry Cook, a computer scientist at Princeton University and avid shell musician, or to allow the player to see over the instrument while walking.

To record the tunes and understand the acoustic context in which the instruments, called pututus, were played, the researchers traveled to Chavín.

As an expert shell musician blew into the horn, researchers recorded the sound's path via four tiny microphones placed inside the player's mouth, the shell's mouthpiece, the shell's main body and at the shell's large opening, or bell. Similar to a bugle, the instruments only sound one or two tones, but like a French horn, the pitch changes when the player plunges his hand into the bell.

The team used signal-processing software to characterize the acoustic properties of each trumpet. Following the sound's path made it possible to reconstruct the ancient shell's interior, a feat that normally involves sawing the shell apart or zapping it with X-rays.

The researchers also wanted to know how the site's ceremonial chamber, a stone labyrinth with sharply twisting corridors and ventilation shafts, changed the trumpet's sound. To find out, the team arranged six microphones around the musician and reconstructed the sound patterns on a computer.

If the trumpets were played inside the stone chamber in which they were found, the drone would have sounded like it was coming from several different directions at once. In the dimly lit religious center, that could have created a sense of confusion, Abel says.

Read more at Discovery News

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