  Using deep Chandra observations of M84 we study the energetics of the
interaction between the black hole and the interstellar medium of this
early-type galaxy. We perform a detailed two dimensional reconstruction of the
properties of the X-ray emitting gas using a constrained Voronoi tessellation
method, identifying the mean trends and carrying out the fluctuation analysis
of the thermodynamical properties of the hot ISM. In addition to the PV work
associated with the bubble expansion, we identify and measure the wave energy
associated with the mildly supersonic bubble expansion. We show that, depending
on the age of the cavity and the associated wave, the waves can have a
substantial contribution to the total energy release from the AGN. The energy
dissipated in the waves tends to be concentrated near the center of M84 and in
the direction perpendicular to the bubble outflow, possibly due to the
interference of the waves generated by the expansion of northern and southern
bubbles. We also find direct evidence for the escape of radio plasma from the
ISM of the host galaxy into the intergalactic medium.
