Fidelity is a fickle thing. The act of adaptation heavily relies upon an artist bringing unique perspectives to preexisting work, whatever it may be. In “The History of Sound,” Oliver Hermanus has handsomely directed Ben Shattuck’s script, one based on Shattuck’s own short story. Aye, there’s the rub. Rigidity is the modus operandi for this gay love story set before, during and in the aftermath of World War I. Rigid is the public expression of love between these two men, rigidity is what one was raised on and what the other eschews yet falls into. Though it may feel apt for a formal rigidity to dominate the film’s craft, this endless standstill quickly proves tiresome.  The saga follows Lionel Worthing, played by Paul Mescal, a musical prodigy whose preternatural sense for sound, known even as a child in 1910 Kentucky, sets him on a path to Boston Conservatory where he befriends fellow David White, played by Josh O’Connor, with whom he falls into a whirlwind romance. The war tears th...