Abstract: A refrigerant compressor discharge muffler which operates on the principle of a closed chamber resonator is disclosed. The muffler includes a generally J-shaped tube and an outer shell adapted to be threadably affixed to the head of a motor-compressor unit. The J-shaped tube is partially disposed within the outer shell and has a plurality of arrangements of apertures extending through the wall of the tube interconnecting the internal passage of the tube with a chamber defined by the outer shell. The spacing and size of the apertures are determined by a relationship to a frequency desiring to be attenuated.