Rome: using resonance to tune public space

listen to the NPR radio show "The Sound of Architecture"

amphora resonating to traffic w microphone, O+A 1991


In Rome in 1992, O+A made a sound installation in support of Peter Erskine's solar spectrum work, Secrets of the Sun. The amazingly rich visual aesthetic of the Trajan's Forum site — with its famous proto-Roman arched Aula by the architect Apollodoris — was, to our ears, completely over-ridden by the bombardment of the noise of Rome traffic passing by on the busy Via 4 Novembre. Trajan’s Forum had now become a band shell for amplifying Fiats and Vespas. Rather than escalate and add a still louder sound of our own, we decided to use this ever-present 20th century sound as our basic material and to seek a method of transforming it.
An exploration of the available sound resources at the site included dropping a stereo mic into a Roman Amphora. While the sound inside the amphora was as all the bells of Rome ringing, on withdrawing the mic it was merely traffic noise. This clay vessel from slave-powered Rome had become — in our fossil-fueled century — an acoustically-activated synthesizer, trapping and resonating the tones of the traffic into a complex pool of shifting harmonics. Low tones of busses would activate a deep fundamental, passing Vespas would make high overtone chords, emergency sirens became solo melodic voices when heard within the echoing clay confines. We secured permission from the archeologist in charge of the Forum to use some of the vessels, and then chose for our use four out of about two-hundred and fifty amphorae, each of which had a different character to its overtone series.We used the traffic sound resonating inside the amphorae, filtered it, amplified it, and projected back in real-time, on-site, a musically tuned version of the urban noise. We chose as our focal point the archway over the old Roman road which was once used as a main entrance to the Forum. There we hung a single ceramic "Planet Speaker," powered by solar panels. The speaker’s focused beam of tuned traffic resonance played across the curved surfaces of the old Roman architecture and transformed the sonic ambiance in a harmonic way. What we could not have foreseen is that, at the exact time the "Traffic Mantra" began to play, an atmosphere of calm descended on the international crew of workers who, up to that point, had been arguing avidly in many languages.