What’s it like to steer clear of the bottom but never quite hit the heights? Masumi Per Rostad on the vicarious life of the viola.

In contentious times, we know the story. Two sides are separated by a great distance, and cannot find their way to unity without a go-between, a trusted, passionate and eloquent guide. A middle voice. Such is the musical challenge of the string quartet. Two high-voiced violins stand at one pole, a single low cello stands at the other. Sandwiched in between, there is this crucial middle voice. The viola.

“There’s only one of you”, says Masumi Per Rostad, violist with the Pacifica Quartet. But that one is mighty. “You straddle worlds of sound, worlds of musical character. Sometimes you’re Eusebius and sometimes Florestan”, he says, referring to Robert Schumann’s invented personality-characters, the first sensitive and quiet, the other outwardly exuberant. The role of violist “requires you to be very mercurial”.

Masumi Per Rostad, Pacifica Quartet Masumi Per Rostad, violist in the Pacifica Quartet. Photo © Keith Saunders

I spoke to Masumi on a Sunday afternoon, while he drove from his home in “Bloomy” (Bloomington, Indiana) to...