The Hagia Sophia in Istanbul was one of the most influential and architecturally significant houses of worship in the medieval world. Built by Byzantine Emperor Justinian in the sixth century, the building has been a religious and political flashpoint ever since, starting as a Christian church, becoming a Muslim mosque, and now existing as a secular museum.
With its contentious past in mind, it’s no surprise that the current custodians have banned worship in the building; most unfortunately, the form of worship it was designed to amplify: singing. But those walls can talk and technology has given us a way to listen, as Cynthia Haven reports in Stanford (September/October 2012).
Since 1934, the building has tantalized lovers of ancient music, like Stanford art history assistant professor Bissera Pentcheva, who have longed to hear what it sounded like to sing in the sacred space. “For a building that had such an important aura or presence, to lose its voice is really dramatic,” said Pentcheva. Fortunately, she didn’t need to look too far to find two people who could give Hagia Sophia its voice again.
At Stanford’s Center for Computer Research in Music and Acoustics, Pentcheva met consulting professor Jonathan Abel, who had previously worked with doctoral student Miriam Kolar on recreating the aural experience of a ceremonial Incan structure with the hope of gaining a better understanding of the sociology of the ancient worshipers. Abel’s expertise includes analyzing, synthesizing and manipulating sound, so the duo was the dream team Pentcheva needed to answer her pressing question.
The trick for Kolar and Abel was to devise a way to record and synthesize the acoustic signatures of Hagia Sophia without actually having to sing in the building. The solution couldn’t have been simpler: “Balloon pops are convenient for probing the acoustics of a space, as they generate relatively uniform radiation patterns and consistent ‘N-wave’ waveforms,” said Abel. In other words, the balloon pop mimics the way a human voice would bounce off the magnificent 182-foot-high dome and 40 arched windows.
Back in the lab, Abel pinpointed the acoustic fingerprint of the balloon pop and designed a computer model that can apply that fingerprint to any piece of music, effectively making it sonically identical to what it would have sounded like in the actual building. Abel then recorded 13 members of the Portland, Oregon-based vocal group Cappella Romana, and placed each voice into the acoustic recreation of Hagia Sophia. The result was surprising to everyone. “The building is super-reflective of acoustic energy,” said Abel. “Sound is smeared out, each note bleeding into the next, rendering speech less intelligible.” Where reverberation in modern acoustic spaces is usually around two seconds, reverb in the Hagia Sophia is a whopping 11 seconds. This suggests that singing and speaking in the space was probably much slower than anyone has ever considered, likely giving an audience plenty of time to absorb the spiritual message.
Cappella Romana’s virtual performance in Hagia Sophia will be presented in a custom-built space on the Stanford campus next February. And as far as Abel is concerned, the four-year project has given him much more than a quick listen to the past. “The space is telling you all these things about it as you’re listening,” said Abel. “It gave me an awareness of what architecture can do for humans.”
Read the entire article at Stanford, a publication of the Stanford Alumni Association.