Not reverberant; lacking a tendency to reverberate(adjective)
WordNet. Princeton University. 2010.
Use "unreverberant" in a sentence
"Once more he called out into the unreverberant silence, but already he was certain that he would never know the answer."
"Every footstep, every word, vanished instantly into the unreverberant void; after they had gone little more than half a kilo - metre, Lt Calvert could stand it no longer."
"Cliff looked around the now familiar, comforting little cabin, and then thought of the lonely emptiness between the stars-the unreverberant abyss through which a man could fall until the end of time."