The reverberation time is larger for an empty hall than for a crowded hall. Why ?

"The reverberation time is larger for an empty hall than a crowded hall". Why?

A hall has a volume of 10000 m^(3) . Its total absorption is equivalentto 400sq. M of an open window. What will be the effect ona reverberation time if audience fills the hall and increases the absorption by another 400sq. Metre of an open window?

The intensity of reverberation is higher in a closed and empty house.

Why the screen of a cinema hall made rough and white?

What is reverberation? What will happen if the reverberation time in a big hall is too long?

Why a given sound is louder in a hall than in the open?

(7)/(9) of the people present in a hall are sitting in (9)/(13) of the chairs available and the rest are standing. If there are 28 empty chairs, how many chairs would have been still empty if everyone in the hall was sitting?