Echo: Echo effects are also time-shifted repeats of a signal, but they are designed to sound like the echo found in nature. Many include ambiance to increase the natural effect. Echo is a form of delay modulation.
Tape Echo: Back in the “old days,” producers and engineers created delay and echo effects using tape machines. A signal would be routed to a separate tape recorder (from the one being used to record the performance) that was set to monitor off its repro head. The slight amount of time that occurred between when the signal was presented and when it finally came off the repro head provided a delayed signal back to the main recording.
The delay time could be adjusted by changing the speed of the tape machine used for the delay. Multiple echo repeats could be generated by routing the delayed signal back into the machine, and other effects, such as chorus and flanging, could be created by changing the speed of the machine while signals were passing through. Many effect pedal manufacturers have tried to replicate the sound of the original taped delays.