Microphones should be kept away from which of the following?

Microphones should be kept away from A/C units, vents, computers, and copy machines because these devices can introduce unwanted ambient noise and electromagnetic interference into recordings. A/C units and vents can create persistent airflow noise, which can disrupt clarity, while the mechanical operation of computers and copy machines may generate hum or other distracting sounds. Ensuring a clean audio environment is crucial for high-quality recordings, and positioning microphones away from such noise sources minimizes the risk of capturing background sounds that can diminish the overall quality of the recording.

While other options present various considerations for microphone placement, the specific challenges posed by electronic devices and airflow make this the most critical area to focus on for achieving optimal audio fidelity.