Echo

The dictionary defines an echo as “the repetition of a sound by the reflection of sound waves from an opposing structure, either natural or man-made.” When a sound reflects off multiple surfaces, as it might in a cathedral, there are huge numbers of discrete echoes and these combine to form the phenomenon of reverberation (usually shortened to reverb). Often the first few echoes in such an environment give us clues as to the size of the structure and these echoes are called early reflections. In music, echo is thought of as a separate effect from reverb and is most often heard produced by a time delay pedal or rackmount module. A popular use of the echo effect is the slapback or slap echo, in which a single echo of approximately 40-120ms is used to enhance vocals or instruments (primarily guitar). The slapback echo first became popular in the 1950s and quickly became a signature effect of rock and roll music. The late John Lennon experimented a great deal in his post-Beatles solo projects with slapback echo, as heard in songs such as “Instant Karma.”