Paralyzed by a debilitating case of rheumatoid arthritis, the Swedish composer Allan Petterson was largely confined to his cramped apartment in a loud industrial neighborhood of Stockholm while writing his Seventh Symphony in 1967. The psychological toll of his surroundings and near-complete isolation courses through the work. A hulking 40-minute monolith, the Symphony is driven by a menacing two-note motif that, like a Rothko color field painting, sluggishly oozes bleak grays and blacks across a colossal orchestral canvas. Christian Lindberg’s 2018 recording with the Norrköping Symphony Orchestra, released as part of an ongoing effort to record all of Pettersson’s orchestral works for Bis, reveals unexpected tenderness in the Symphony’s broad brushstrokes, aspiring to what the composer called the ultimate aim of his music: “to rediscover the song once sung by the soul.”