Delay – Repeats the input signal after a predetermined time interval
Think of delay as a parrot.
Basic delay looks like the following.
Delay can be used in lots of ways. It can be used to reproduce the original sound to the same sound pressure level after a set time delay only once as above.
Or, the sound can be repeated as many times as you want.
You can even repeat the sound at the same time delay but at half (50%) of the sound pressure level as before.
Now the delay is turning into an echo but the difference is that you can control every aspect of the repeat from sound pressure level to time delay.
Sometimes musicians delay the repeat to be in time with the beat of the music (beats per minute). As you play your second note, the first note would come back in as well, giving you a new sound.
Music delays may work in solo's, but often won't work when guitars are played for rhythms. You have to experiment with a song to know when to switch the delay off and on.