Phase

When recording with more than one microphone, a couple of mics on an acoustic guitar, or several microphones on a drum kit, for example, it’s important to be aware of potential phase issues. Signals entering the preamp can become out of phase when the sound captured by one microphone is overlapped with a delayed signal of the same sound captured by another microphone which is further away from the source. The signal from the second microphone arrives at the input of the preamp slightly later than that of the first microphone. This causes peaks and dips in the frequency response, resulting in comb filtering—a hollow and unnatural sound. Phase issues are most noticeable on low frequencies. A signal that’s out of phase will sound thinner than when it is in phase.