A compressor (10) comprises counter rotating and intermeshing twisted rotors (18) and (20) disposed in a housing having an air intake plate (28) and an outlet (16). The outlet (16) has a first edge (60) and a second edge (70) which nm parallel with a length of the rotors (18) and (20) respectively. A gap (62) is formed in the outlet near a junction of the edges (60) and (70). Air which is compressed by the rotors (18) and (20) is able to bleed through the gap (62) in advance of trailing edges of lobes of at least one of the rotors (18) passing its corresponding edge (60). Also the rotors (18), (20) are arranged so that the trailing edge of a lobe of rotor (18) passes edge (60) before a trailing edge of a lobe of rotor (20) passes edge (70).