The present invention relates to an apparatus casing for a computer, comprising a number of walls ( 21, 22, 23, 24, 101, 103, 104, 105, 106, 107 ) which together define a first chamber ( 20, 200 ) for accommodating computer components (A, B, C), a
noise attenuating inlet ( 30 ) which includes an inlet duct ( 31, 310 ) and an inlet opening ( 32, 320 ) that opens into the first chamber for supplying air from the surrounding
atmosphere to the first chamber via the inlet duct and the inlet opening, a
noise attenuating outlet ( 40 ) which includes a first outlet opening ( 42, 420 ) and an outlet duct ( 41, 410 ) for dispelling air from the first chamber to the surrounding
atmosphere via the first outlet opening and the outlet duct, and a fan ( 45, 450 ) for producing an air flow through the inlet, the first chamber and the outlet. The invention also relates to a computer that includes one such apparatus casing.