Function of Bhavanga - Bhavanga-cittas and the sense-door process
When the stream of bhavanga-cittas has been arrested, the ear-door-
adverting-consciousness (sota-dvaravajjana-citta) adverts to the object
through the ear-door. This citta can be followed by other cittas which each
perform their own function in that process before it falls away. Rūpa lasts as
long as seventeen moments of citta counting from the atīta-bhavanga, the
past bhavanga, there can be seventeen moments of citta succeeding one
another if the sense-door process runs its full course. If the rūpa which will be
object has contacted more than one atita bhavanga, it will have fallen away
before the process can be completed, since it cannot last longer than
seventeen moment of citta. A process can, after it has started, be
interrupted, for example, after the votthapana-citta, before kusala cittas or
akusala cittas can arise. It may also happen that the atīta-bhavanga is
succeeded by the bhavanga-calana, but that the bhavangupaccheda does not
arise; then there will be no process of cittas. Sound may, for example,
impinge on the ear-sense and then the atīta-bhavanga which arises is
succeeded by the bhavanga-calana. However, the bhavangupaccheda does
not arise and thus the stream of bhavanga-cittas is not interrupted and the
ear-door process cannot start. In that case the sound cannot be heard.