Yes, fans spinning at high speeds can generate sound waves that can be picked up by microphones. The sound produced by a fan typically consists of low-frequency noise or a steady hum, depending on the specific fan design and speed.
To minimize the interference or distortion caused by fan noise when recording audio, you can consider using certain types of microphones that are less sensitive to low-frequency sounds or have specific features to mitigate such noise. Here are a few microphone options to consider:
Dynamic microphones: Dynamic microphones are known for their durability and ability to handle high sound pressure levels. They are generally less sensitive to low-frequency noise compared to other microphone types. Due to their construction, dynamic microphones tend to have better off-axis rejection, which means they are less likely to capture sound from the sides and rear, potentially reducing fan noise pickup.
Shotgun microphones: Shotgun microphones are highly directional and have a narrow pickup pattern. They are commonly used in film and video production to capture sound from specific sources while rejecting ambient noise. By pointing the shotgun microphone towards the desired sound source and away from the fan, you can minimize the pickup of fan noise.
Boundary microphones: Boundary microphones, also known as PZM (pressure zone microphone) or boundary plate microphones, are designed to be placed on surfaces such as walls or tables. They utilize the reflective properties of surfaces to enhance their pickup. By placing a boundary microphone closer to the sound source and away from the fan, you can minimize the fan noise pickup.
Additionally, using shock mounts or microphone isolation devices can help reduce vibrations and mechanical noise transmitted from the fan to the microphone.
It's important to note that even with appropriate microphone selection and positioning, some residual fan noise might still be present in the recording. In post-production, you can further reduce or eliminate unwanted fan noise using noise reduction tools or equalization techniques.