  We calculate the third cumulant of current in a chaotic cavity with contacts
of arbitrary transparency as a function of frequency. Its frequency dependence
drastically differs from that of the conventional noise. In addition to a
dispersion at the inverse RC time characteristic of charge relaxation, it has a
low-frequency dispersion at the inverse dwell time of electrons in the cavity.
This effect is suppressed if both contacts have either large or small
transparencies.
