Abstract: This paper deals with the additional displacement of the modulation ring of air stream sound source caused by Bernoulli force and gives formulas and charts for calculation. At the same time, the paper discusses the selection of the best parameters and analyses the contribution of different frequency band for speech intelligibility and determines frequency band of a electropneu-matic loudspeaker. Some parameters were tested. The characteristics of the developed electropneu-matic loudspeaker are good. The sound pressure frequency responce is flat between 200 Hz and 2000 Hz. In the magnetic gap the flux density reachs 1.9Wb/M² and the sound pressure level is 120 dB at a distance of two metres from the born mouth.