When last at the Kimmel Center's Perelman Theater, mezzo-soprano Anne Sofie von Otter had such a blue-chip opera career that hearing her in a smallish theater such as that was a coup. Now, at 60, having sung nearly everything suitable to her mid-weight mezzo voice, she has arrived here with the kind of program singers assemble when they have nothing to lose.
The repertoire was early baroque - some of the English selections being Elizabethan-era - with composers such as Dowland, Purcell, and Lambert, not often heard outside early-music festivals. She was accompanied on chamber organ and harpsichord by Jonathan Cohen and on lute and theorbo by Thomas Dunford. Opera seemed a million miles away with music that dictated smaller-scale vocalism, words over tone, and intimacy of expression.
Otter has long been a restless singer, repeating repertoire infrequently, always moving forward, never establishing signature pieces, often communicating more with her warm tone and charismatic personality than with stylistic depth. So it was in this highly specialized program. Her singing didn't have the authority you'd hear from Emma Kirkby, though Otter's manner was that of someone eager to share her affection for what she was singing. In her best moments, she entered the zone of an Elisabeth Schwarzkopf - a similarly patrician singer whose manner could be infectiously extroverted.
Periodically, Otter sat off to the side when Dunford played solo works, drawing you in with a degree of soft playing that was occasionally just a shade above audibility. In that sense, the concert was radically antique - and all the more lovable for it. It was also underrehearsed, the French music on the second half going less well than the English music on the first. And in the English set, some of Purcell's more eccentric musical characterizations weren't worked well into her voice, leaving you wondering what the music was trying to say.
Near the end, though, Otter closed the three-to-four-century gap between her audience and the music with pop songs drawing on the manner of their ancestors, Björk's "Cover Me" going particularly well, although Bruce Springsteen's "Philadelphia" seemed barely learned.
Even rickety moments were winning, and you had to applaud Otter's enterprise in presenting a program that would be considerably less appealing to Philadelphia Chamber Music Society audiences without her career equity. Most singers consolidate during their late-career seasons. Otter continues expanding.