Archeo-acoustics Round-up

This article in Discovery Magazine covers a lot of what archeologists have been discovering about the acoustical properties of ancient sites, and then talks about one I hadn't heard of before in central Peru.

The most detailed evidence of ancient acoustical design comes from the Stanford team studying Chavín de Huántar, which was constructed between 1300 and 500 B.C. Peruvian archaeologists first suspected the complex had an auditory function in the 1970s, when they found that water rushing through one of its canals mimicked the sound of roaring applause. Then, in 2001, Stanford anthropologist John Rick discovered conch-shell trumpets, called pututus, in one of the galleries. The team set out to determine what role the horns played in ancient rituals and how the temple may have heightened their effects. Archaeoacoustics researcher Miriam Kolar and her collaborators played computer-generated sounds to identify which frequencies the temple most readily transmits. Over years of experiments, they found that certain ducts enhanced the frequencies of the pututus while filtering out others, and that corridors amplified the trumpets’ sound. “It suggests the architectural forms had a special relationship to how sound is transmitted,” Kolar says. The researchers also had volunteers stand in one part of the temple while pututu recordings played in another. In some configurations, the sound seemed to come from all directions.

The Caveman Principle

This interview with a physicist talking about the future makes for a fascinating read for a geezer like me. The following paragraph really jumped out:

Take the paperless office. Futurists predicted that the computer would make paper obsolete. Now, however, we use more paper than ever. Techies overlooked what Mr. Kaku calls "the Caveman Principle": the fact that "our personalities haven't changed for 100,000 years, since modern humans emerged from Africa." The scientist likes high tech, "but the caveman likes high touch," he explains. "People don't feel comfortable with all the electrons on their PC screen." With the flip of a switch, those electrons disappear, worrying our inner caveman. "We want a hard copy."

Lately I've been thinking, for a number of reasons, that live music in various non-standard formats is a niche waiting to be filled by musicians. This quote suggests one I hadn't thought about, that on an evolutionary level we're not that different from our distant ancestors and that maybe live music supplies us something that will always be absent from recorded music. Maybe something about the way we like live music is sort of like our appreciation of the hard copy Mr. Kaku uses to explain our connection to our pre-historic selves.

More Archaeo-Acoustics

Here's another story that's popped up on the sound properties of ancient monuments. The focus of the article is a 6,000 year old megalithic temple on Malta.

Low voices within its walls create eerie, reverberating echoes, and a sound made or words spoken in certain places can be clearly heard throughout all of its three levels. Now, scientists are suggesting that certain sound vibration frequencies created when sound is emitted within its walls are actually altering human brain functions of those within earshot.

"Regional brain activity in a number of healthy volunteers was monitored by EEG through exposure to different sound vibration frequencies," reports Malta temple expert Linda Eneix of the Old Temples Study Foundation, "The findings indicated that at 110 Hz the patterns of activity over the prefrontal cortex abruptly shifted, resulting in a relative deactivation of the language center and a temporary shifting from left to right-sided dominance related to emotional processing and creativity. This shifting did not occur at 90 Hz or 130 Hz......

In addition to stimulating their more creative sides, it appears that an atmosphere of resonant sound in the frequency of 110 or 111 Hz would have been “switching on” an area of the brain that bio-behavioral scientists believe relates to mood, empathy and social behavior. Deliberately or not, the people who spent time in such an environment under conditions that may have included a low male voice -- in ritual chanting or even simple communication -- were exposing themselves to vibrations that may have actually impacted their thinking." [1]

But the Hypogeum is not alone in its peculiar sound effects. A study conducted in 1994 by a consortium from Princeton University found that acoustic behavior in ancient chambers at megalithic sites such as Newgrange in Ireland and Wayland's Smithy in England was characterized by a strong sustained resonance, or "standing wave" in a frequency range between 90 Hz and 120 Hz. "When this happens," says Eneix, "what we hear becomes distorted, eerie.

As I said in a previous post, I'm always a bit suspicious when people try to say exactly what and why people were doing things 6,000 years ago, but the evidence does seem to indicate the ancients were not unaware of how sound can be an effective part of rituals.

Sound Awareness of the Ancients

Here are two articles talking about research presented at the annual meeting of the American Association for the Advancement of Science. One by the BBC is mostly about Stonehenge and how the placement of the standing stones closely maps the sound interference pattern of two flutes being played at the center of the site.

Another at InsideScience includes information about other sites such as Chichen Itza, where the echo of a hand clap in front of the stepped monument comes back as a chirp. Having been there and experienced the phenomenon first hand, I can say it's a very striking effect that seems to be more than happenstance.

These articles reminded me of visiting "Agamemnon's tomb" in Greece, and having had some time alone in it between tour groups. The video at the link gives a taste of the reverberation inside it, and I'd find it hard to believe the people that built it didn't notice the acoustics and put them to use somehow.

The InsideScience article also mentions something I'd seen before, that cave paintings are often in the most acoustically interesting parts of the caves.

I always wonder how anyone can say with any certainty what the people of those long ago times were up to, but since all the new neuroscience points to just how important sound and music are to the human brain, that they were aware of that in their own way and somehow put it to use wouldn't surprise me at all.

Archeo-acoustics

This article is a nice round up of what various people think about the importance of sound to our ancestors. It's the sort of thing we'll never know for sure about, but is fun to speculate on.

I've always had great respect for the awareness the ancients had for sound ever since visiting Epidarus on my first backpacking trip to Europe in 1976. I was sitting high up in the theater seats when a tour group came through and the guide had them spread out all through the seats. He stood at the center of the stage and struck a match and it was perfectly audible to all of us. Simply amazing.

Acoustics

Acoustics have a lot to do with the effects of music (or just simple sound) on the listener. This is a link to an extreme example, Mayan ball courts. The structure was apparently built with sound effects in mind. The thing about acoustics is that providing for them in structures seems to be as much art as science. One often hears of new concert halls with poor acoustics and of older halls with wonderful acoustics. Part of the problem might be that with the advent of recorded music, people (including architects) are spending less time in concert halls, so they're naturally less familiar with what does and doesn't work.