England’s Adult Jazz recall Boston’s Gem Club: the music is thoughtful, spare, experimental, both serene and unsettling, and at times heartbreakingly beautiful. Where Gem Club are a duo (with cello, piano, and voice), Adult Jazz are four musicians, and their electronic washes and drones get equal play with percussion (both lumbering and spidery), keyboards of varying kinds, horns, and vocals that morph from quiet to jazzily swinging, depending on a tune’s direction at any given moment. They have a playful core, which sparkles with a wry and childlike wit on “Am Gone” and a degree of melancholia on “Springful,” with its springy bed of guitar notes and clattering bones. Harry Burgess’ falsetto is utterly beguiling; the stunning seven minutes of “Hum” showcases Burgess’ limber delivery and remarkable grace, and on the more lighthearted “Donne Tongue,” acerbic lashes surprise and lend the tune another facet. The nine-minute “Spook” is a mini-epic of horns, drums, guitars, and vocal ups and downs that are wrought as a floating, buoyant, cabaret tune.