A ritual sensibility pervades “Diaries,” a new track by the Polish musician Martyna Basta. The pace is slow, the mood pensive. Her wordless voice floats like incense; the reverb suggests the stone walls of a very old church; she plucks out the song’s rubato zither melody with the care with which one might touch a flickering match to a votive candle. Unidentified rustling and crackling signals the presence of unknown figures in the shadows, as though the presence of ghosts had been picked up on tape. The overall effect is a powerful sense of mystery shot through with mournful grace. Much like her album Slowly Forgetting, Barely Remembering, released this spring, “Diaries” uses minimal elements to evoke elusive, outsized feelings.