The Phaser (ˈfāzər) is an effect used to elicit a psychedelic sound in electric guitars. The sound signal of the guitar is altered through the addition of peaks and troughs in the music’s frequency. The phaser splits each audio signal into two distinct paths. The phase of one of the paths is altered so that the frequencies of the two paths will cancel each other out. When the signals are canceled out, the sound leaving the guitar becomes swirly. Phasers were very popular during the 1970s. Although they died out for a period of time, their effects can still can be heard in primarily in guitar solos today.