The PHAZER Phase Alignment Tool from Radial Engineering Limited is an analog phase correction device designed to time-align 2 signals so that the fundamental frequency of both signals play at the same time. For instance, you may have one microphone on the batter-head of a kick drum for more attack, while a second microphone may be on the outside of the drum to add body. When the kick-pedal strikes the batter-head, the sound of the first head will occur slightly before the second. Delaying the sound of the first head allows you to play both at precisely the same moment, which will produce a rich tone. This same approach is particularly effective with guitar amplifiers when combining a direct feed from a guitar amp with a microphone on the cabinet or when combining 2 room microphones, such as a close microphone on an acoustic guitar and a second microphone to pick up the room ambiance. 

As it is physically impossible to time-align all frequencies due to each harmonic having a different wavelength, the Phazer Phase Alignment Tool must be heard to be effective. By listening to the tone as you rotate the phase control, you will hear when both sounds come in focus and will be able to find the sweet spot.

As this is most evident when the lower fundamentals align, this tool is also equipped with a low pass filter that rolls off high frequencies above a variable cut-off point to help reduce phase anomalies in the upper spectrum.