Metamaterial members for absorbing sound and pressure, and modular systems built of metamaterial members are provided. The metamaterial member includes an outer mass. The outer mass can have a cavity formed therein in which a stem coupled to an inner mass is disposed, or the outer mass can be solid and contain an inner mass embedded therein. The inner mass can include an inner core and an outer shell. Multiple metamaterial members can be attached to form a modular system for absorption of sound and pressure.