Abstract: An acoustic absorbing panel adapted for use with computers and servers includes a first layer and an opposing second layer, and a core disposed between the first and second layers, the core including walls extending between the first and second layers and defining a series of cells, each cell being at least partially surrounded by a wall, adjacent cells being interconnected via an opening in the at least one wall. The panel includes a through hole in the first layer or the second layer. The hole may be aligned with a cell in a series of cells. The panel has an absorption band at a frequency between 800 Hz and 12000 Hz. The panel may include a flame resistant polymer composition. The panel may be mounted on the frame of an electronics enclosure. The electronics enclosure may be a server rack or a case of a computer or server.