The term 'EFFECT ECHO' is composed of two words, 'EFFECT' and 'ECHO'. EFFECT is a noun that refers to a change that results from an action or other cause. ECHO is a noun that refers to a sound or series of sounds that is reflected off a surface and heard again by the listener. The crossword solution for this term is 'REVERB', which is a noun that refers to the reflection of sound waves off a surface, creating a reverberating EFFECT. REVERB is often used in music production to create a sense of space and depth.