The present invention relates to a method and a device for controlling at least one drill parameter when drilling in rock with a drilling machine. During drilling, an impulse-generating device uses an impact means to induce shock waves in a tool working against the rock, a pressure level for a shock-wave-generating pressure is controlled during the drilling, and said drilling machine includes a damping chamber that can be pressurized. The contact of the drilling machine against the rock is affected at least partially by the pressure prevailing in said damping chamber. When the pressure in said damping chamber exceeds said first level and is below said second level, the percussion pressure is controlled as a function of the pressure in said damping chamber.