Sound softened by acoustic foam (4)
I believe the answer is:
echo
(Other definitions for echo that I've seen before include "repeated answer" , "Reverberation of sound" , "Sound heard before" , "Languishing nymph" , "Repeat or reverberate" .)
I believe the answer is:
echo
(Other definitions for echo that I've seen before include "repeated answer" , "Reverberation of sound" , "Sound heard before" , "Languishing nymph" , "Repeat or reverberate" .)