  We report the theory of the \emph{dynamical response of current fluctuations}
of a photo-excited conductor. We have performed the calculation for a coherent
conductor described by arbitrary energy-dependent transmissions and for
arbitrary frequencies. We consider two experimental setups that correspond to
different ways of symmetrizing the current operators, leading to different
predictions. Our results are in very good, quantitative agreement with a recent
measurement. We demonstrate that the dynamical response of noise that we have
calculated is the key concept that relates Dynamical Coulomb Blockade, i.e. the
electron-electron correction to the conductance due to the presence of an
external impedance, to quantum noise.
