In a ventilated cigarette making system the tipping paper is perforated before assembly of the cigarettes using a spark perforator which is controlled by a feedback arrangement, in response to the resultant air permeability of the finished cigarettes, or the permeability of the tipping paper as monitored before assembly. Preferably the testing of the finished cigarettes is done in a modified Molins "CID 4" cigarette testing device. The averaged test signal is used to control the frequency of power supply to the spark perforator, whose electrodes are loaded with capacitors so that the change in frequency results in a change in the current flow through the electrodes, and thus the size of the holes produced.