Echo. The echo sound effect is often called "Echo" or "Reverb" in music production. Echo refers to adding one or more repeated sound effects to the sound signal to make the sound heard by people feel like an echo. Reverb refers to adding a reverberation effect to the sound signal, causing the sound to reflect and refract in the space, producing echo and reverberation, making the listener feel that the sound is broader, deeper and more natural. These two sound effects are usually used in song mixing, concert scenes, movie soundtracks and other occasions to enhance the layering and environment of the sound, making it easier for the audience to immerse themselves in the music.