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
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.
Image courtesy of MiGowa, licensed under Creative Commons.