A noise suppression panel having a first cellular core positioned between and bonded to an imperforate facing sheet on one surface thereof and a first sheet of microporous material on the other surface. A second core is bonded between the other surface of the first sheet of microporous material and a perforated sheet. The other surface of the perforated sheet has a second sheet of microporous material bonded thereto. The cells of the two cores are preferably substantially aligned when maximum core-to-core bonding strength therebetween is required. A method of manufacturing is disclosed which includes flow-through resistance testing of the subassemblies.