Eventide Inc. is an American pro audio, broadcast and communications company whose audio division manufactures digital effects processors, digital signal processor (DSP) software, and guitar effects pedals. Eventide was one of the first companies to manufacture digital audio processors, and its products are mainstays in sound recording and reproduction, post production, and broadcast studios.

A phaser is an electronic sound processor used to filter a signal by creating a series of peaks and troughs in the frequency spectrum. The position of the peaks and troughs of the waveform being affected is typically modulated by an internal low-frequency oscillator so that they vary over time, creating a sweeping effect.