Stephen Sondheim celebrated his 80th birthday in March in a Lincoln Center concert that will be broadcast on PBS this fall. The festivities continue this weekend as Sondheim is the focus of two concerts on the same day, nearly 4,000 miles apart: at the Ravinia Festival Pavilion outside Chicago and at London's Royal Albert Hall for BBC Proms Saturday night. Sondheim is the BBC Radio 3 Composer of the Week.

The Black Keys performed their second and third consecutive sold-out shows in New York City last night, at SummerStage in Central Park and at Terminal 5. The New York Times says: "At their best and starkest, they can make a growling riff feel loose and woozy, tempos fluctuating as if on a column of air." The New York Post says they "made an incredible amount of music for two guys who obviously know size doesn’t matter when it comes to the blues ... [T]he guys were unstoppable."

The 45th annual Cambridge Folk Festival gets under way tonight at Cherry Hinton Hall in Cambridge, England, and three Nonesuch artists are set to take the stage there this weekend: Natalie Merchant headlines Saturday night, Carolina Chocolate Drops perform both Saturday and Sunday, and Rokia Traoré performs on Sunday. BBC Radio 2 will broadcast highlights next Wednesday.

Nonesuch Records is set to release violinist Gidon Kremer’s De Profundis, featuring the Kremerata Baltica chamber orchestra, on September 14. The album’s 12 pieces, selected from Kremer’s performing repertoire, span nearly two centuries, from Schubert to Schnittke—artists who sought to "sustain humans by appealing to their profoundest emotions," says Kremer. De Profundis is available for pre-order in the Nonesuch Store.

Emmylou Harris was among the stellar line-up of performers who gathered to celebrate the music of Paul McCartney at the White House early last month as President Obama presented McCartney with the Gershwin Prize for Popular Song from the Library of Congress. The event, also featuring performances from McCartney and Stevie Wonder (the first recipient of the award) among others, will be broadcast on PBS stations tonight.

Natalie Merchant's tour resumes in the US next week following a stop in the UK for the Cambridge Folk Festival this weekend. Fans on both sides of the Atlantic can now pick up an iTunes Session from Merchant with reimagined original music and cover songs. The Grand Rapids Press gives 3.5 of 4 stars to a recent show, full of "compelling songs, tight musicianship and Merchant's strong vocals."

There's one month to go before the August 31 Nonesuch release of Philip Selway's solo debut album, Familial, now available for pre-order. Selway spoke with Pitchfork about the new project, which it describes as "10 hushed folk songs in the shadowy tradition of Nick Drake. The album is quiet, but there's an unnerving sense of dread that connects the material to his main gig; it's music for a foreboding twilight."

The Black Keys have kicked off their North American tour, offering the home-state crowd in Cleveland their "most superlative-sapping local performance to date," raves the Cleveland Plain Dealer. "Eardrums were ravished. Minds were blown. And when singer-guitarist Auerbach and drummer Patrick Carney finally made their exit, sweat-soaked and utterly spent, it was no small wonder that the downtown skyline was still standing." Pat and Dan's fathers appeared on WKSU radio to offer their unique perspective on the band.

Christina Courtin recently performed a number of songs off her Nonesuch debut album for a Daytrotter Session, now available online. The session features the songs "Green Jay," "Foreign Country," "Jackson," "Bundah," and "Hedonistic Paradise." Says Daytrotter: "There's sadness in her pretty voice, but there's also this kind of big-eyed wonder in it."

With Stephen Sondheim's A Little Night Music back on Broadway, and the legendary Elaine Stritch having joined the cast as Madame Armfeldt, the New York Times looks at the women to have taken on the iconic role; the Times also profiles the small London theater where this revival began. The San Jose Mercury News calls the cast album "extra-clear and intimate." The BBC Proms celebrates Sondheim's music this Saturday; The Times of London calls him "the man who has revolutionised the musical ... sardonic, jaded—and touched with genius."

Ben Folds plays Kansas City and Louisville, talks to Australia's Triple J ... John Adams's Doctor Atomic Symphony receives Australian premiere ... The Black Keys kick off US tour ... Gidon Kremer, Kremerata Baltica finish at Finnish fest ... The Low Anthem tours East Coast ...  Audra McDonald performs at Aspen benefit ... Natalie Merchant tours Midwest ...  Pat Metheny Group concludes European tour ... Punch Brothers are up in Alaska ... and more ...

Natalie Merchant brought her Leave Your Sleep tour to the Chicago Theatre for what the Chicago Tribune calls an "uplifting show," in which Merchant's "multimedia presentation enchanted with childlike wonder and wide-eyed imagination." The Tribune cites her "refreshing enthusiasm and approachable demeanor" and, most important, her "tender, intimate voice."