The disclosure concerns a sound dome which is positioned over the motor housing of a bypass type vacuum cleaner. The main housing outlet for the main blower fan of the vacuum cleaner opens under the sound dome. The dome outlet from the sound dome is spaced away from the main housing outlet, causing the air from the main housing outlet to be redirected to the dome outlet. The motor housing has a tower portion that extends up into the sound dome. The housing has a cooling air inlet for cooling air to the motor, which is located higher up on the tower, and has a cooling air outlet for air that has cooled the motor, which is located lower on the tower. A baffle in the sound dome separates the cooling air inlet and the cooling air outlet. The enlarged plenum defined by the sound dome and the indirect pathway between the main housing outlet and the exit from the sound dome tend to reduce the noise generated by the vacuum cleaner.