As a teenager in the 1980’s, I listened to a lot of U2. I loved their early work with Steve Lillywhite, but the albums produced by Brian Eno and Daniel Lanois took U2 into a more ambient direction. One of the most distinctive sounds of the Eno/Lanois collaboration with U2 is a reverb effect with octave swell. You can hear this on the “infinite” guitar in “With or Without You”:

The effect is more prominently featured on the instrumental “4th of July”:

Nowadays, this effect is referred to as the “shimmer” effect. Judging from browsing a bunch of forums, a lot of people have tried to figure out how to get this sound with current gear. Over the next week, I will discuss the shimmer effect in more detail, with some examples of its use pre-U2, and a detailed technical analysis of what is going on inside the effect.