Two alternative schemes of a pulsing subsonic air efflux from the receiver with an elevated pressure to the atmosphere have been investigated. The 1st efflux takes place only through the closing unit, the 2nd one - through the closing unit which has the attached cylindrical pipe of the long extending. The frequency dependences of flow rate were obtained. It was established that the pipe presence (the 2nd scheme) can cause a change up to 20 per cent in the flow rate at resonance frequencies and the flow rate increase over a range of moderate frequencies (10 - 80 Hz) when compared two schemes at the same action frequencies of the closing unit operating in the pulse mode of gas efflux.