Final answer:
To prevent acoustical phasing issues with multiple microphones, follow the 3:1 rule by placing them at least triple the distance from one microphone to its sound source.
Step-by-step explanation:
To reduce the chance of acoustical phasing problems when using more than one microphone at the same time, place no two microphones closer than three times the distance between one of them and its sound source. This is known as the 3:1 rule in sound engineering. This guideline helps to avoid the overlap of sound waves which can cause interference and affect the quality of the recording.
For instance, if a microphone is placed 1 meter from its sound source, the second microphone should be placed at least 3 meters away from the first microphone. This spacing reduces the chances that sound waves will arrive at the microphones with enough delay to cause phase cancellation.