An engine assembly includes a combustor wall with a first skin, a second skin, a core and a sound attenuation passage. The first skin forms a peripheral boundary of a combustion volume on a first side of the combustor wall. The second skin forms a peripheral boundary of a plenum on a second side of the combustor wall. The core includes a plurality of resonator elements between the first skin and the second skin. A first resonator element includes a first base and a plurality of first protrusions projecting out from the first base. Each first protrusion includes a first bore fluidly coupled with a first cavity within the first base. The sound attenuation passage extends within the core and is fluidly coupled with the combustion volume through an attenuation passage aperture in the first skin. The sound attenuation passage is fluidly decoupled from the plenum by the second skin.