The experience of high-frequency pneumatic hammer design to run on increased compressed-air pressure is reviewed. Arrangement of a coupled shock-pulse generator composed of two pneumatic hammers is described, and its stable operation conditions are determined. The synchronized operation of the hammers in the coupled generator is implemented through the smooth percussion frequency control of one of the hammers. After the accomplished research into interaction between soil and some prototype models with two percussion masses, a fully phase- and frequency synchronized machine has been designed.