One can hardly be a member of the Barbershop Harmony Society without being familiar with the work of David Wright. David's achievements span historical research, arranging, directing, coaching and teaching -- not to mention being a delightful guy and trusted mentor.
Also, he has a day job: Chairman of the Mathematics Department at Washington University in St. Louis. We said he was smart, right?
Now, we all know about just intonation -- we live and die by ringing chords by nudging around just so. Well, David recently brought that practice, and the mathematics that describe it, to a prestigious forum: the annual meeting of the American Association for the Advancement of Science. As reported in Ars Technica:
One particularly enjoyable and informative highlight was a session on Mathematics and Music, which presented some work in progress by three prominent researchers in this area.
The highlight here was a recording of a barbershop quartet in which Wright discovered a subtle use of microtonics during a chord change. In shifting from one chord to another, three of the singers changed notes, while the fourth held on to his note across the chord change—or should have, based on the notes on paper. In practice, the sustained note shifted frequency by a small fraction of a semitone to maintain just intervals with the notes of the second chord.