As another Conspirare season comes to a close, the director of Austin's multiple Grammy-nominated choir is already rearranging the stacks in his office, readying himself for next year's clean musical slate.

Craig Hella Johnson's workspace, tucked behind South Congress Avenue, is quiet and unfussy, filled with soft northern light from French windows that look onto a rooftop and a neighboring oak tree. The boxes of music and files undergoing a seasonal shift are making way for next year's landmark season, Conspirare's 20th.

And what an anniversary it's shaping up to be. After launching a major gifts campaign — spearheaded by a $1 million donation in April from the Kodosky Foundation, the choir's largest to date — it was decided the funds should expand new recordings and commissions of new works.

"What we feel is right, right now, is to make more music with this," Johnson says. "I feel like we're just getting started."

One commission that is sure to garner attention is a new work from Kevin Puts, the 2012 winner of the Pulitzer Prize.

"We thanked him for that," Johnson says, smiling at the impeccable timing. "We loved him before."

The Puts work will be recorded in a flash at Bates Recital Hall. "We have noon to midnight, and we're going to just try and hit it," says Johnson. That recording will appear alongside another Puts work, written for the Baltimore Symphony under famed conductor Marin Alsop.

And that's just the start: Two more recordings are planned, including works from Rachmaninoff and Robert Kyr. All of this will happen as Conspirare's latest record, from their dark and brilliant Samuel Barber program, comes out in October. The Barber recording, Johnson says, was a chance "to burrow in" to the music, with marathon sessions that are physically and spiritually taxing. "I saved ‘Agnus Dei' for last," he says of Barber's iconic work. That was "kind of a gamble," he adds.

But that exhaustion also pulled something special out of the singers, who by now are used to these musical marathons. "We have a shorthand," he says.

Johnson brings up the impact of the 2008 recession. "I feel tremendous gratitude," he says, for "colleagues, a city that has held us and supported us." It is no stretch to say that the palpable connection Conspirare has forged with its audience is, above all, due to Johnson, who, in person, exudes an aura of positivity.

He often explains to his audience that they are participants, that "it's your resonating bodies" that create the space.

The end of a season is never really much of an end for Conspirare. This week's Austin concert is part of the Victoria Bach Festival, which Johnson also directs. They'll sing Handel's "Dixit Dominus," and Arvo Pärt's "Berliner Messe." Johnson wrote a dissertation on Pärt at Yale, at a time when the faculty were asking, "Who is this? He's Estonian?" Johnson had acquired a bootleg Pärt recording (those were the days), and says "a year later, he blew up."

"Sometimes I call him a spiritual minimalist," Johnson says. "There's no rhythmic motor in his music."

Pärt, a pacifist, also gave Johnson what he calls "a Rite of Spring experience," with an audience at intermission who were by turns upset and enthralled.

Johnson shifts to his 1917 Steinway and plays the opening of Pärt's "Credo," actually Bach's "Prelude." It was Pärt's deconstruction of this work that so moved the audience.

Part of Johnson's creative impulse is to expand his own musical collaborations — a founding idea behind his "Company of Voices." Next year, that notion will take him into a unique collaboration with Austin slam poets, who clearly enthrall him. The poets are "always authentic," he says.

The office is remarkably quiet. A dove calls nearby. With a full slate for next year and beyond, one wonders when Johnson takes a break.

"August has a little promise," he says with a smile.