When recording video sound in the field, every shot requires the choice of a specific microphone. Doing interviews is totally different from recording natural sound, and working in rainy, windy weather conditions is always challenging in a unique way. Making a quick choice of the right mic to use in a given situation is essential to being a good location sound recordist.
A typical sound operator carries several key types of microphones in the sound kit. On a very basic level, there will be a dynamic, omnidirectional handheld mic; a shotgun microphone with wind and shock protection; several lavaliers; and at least two wireless microphones.
The trick to getting consistently good audio is to choose the right type of mic and place it correctly for recording the sound source. Much of this choice is grounded in basic knowledge of what microphones can and cannot do, as well some engineering knowledge of mic pickup patterns and directionality.
Once the sound operator knows his or her gear well, recording with the correct equipment becomes almost second nature. The job becomes instinctive and the choices come easily.
Most important is to know is the difference between the types of microphones. The omnidirectional dynamic handheld has long been the staple of news and documentary crews. It is climate resistant and perfect for quick and dirty interviews, standuppers and use with a wind sock on breezy days. These mics are rugged and can take an amazing amount of abuse.
Dynamic handhelds are even used by struggling reporters in raging hurricanes. Every sound kit should have at least one omni dynamic when any other mic would be at risk.
Another reason for these mics is the omnidirectional pickup pattern captures all the ambient sound around the mic. These are very forgiving for off-axis sounds. Because these mics pick up sound 360-degrees, they have no proximity effect, which is the boost in low-frequencies when one speaks within a foot from the microphone.
Some crews also add a handheld cardioid condenser mic, which is brighter and more sensitive to sound pickup when being held at a distance. These mics are more prone to proximity effect when used up close, but they can help cut through the background noise in some loud environments.
Also useful for interviews are lavalier microphones. These tiny clip-on mics are mounted on the subjects’ body and stay in one place. Placement of lavs is often critical, depending on whether the mic needs to be completely hidden from the camera’s view. There are a whole set of tricks for effectively hiding lavs.
Lavs are either straight-wired to the camera, to a double-system sound recorder or to a wireless transmitter. For video recording, omni directional lavs are most popular because they pick up the ambient sound around the subject and are more forgiving to wind noise. Cardioid lavs are best when used in noisy, wind-free environments where loudspeaker feedback is an issue.
Lavalier mics come in a range of models designed for specific functions. Professional models go from $100 up to $600, depending on their design. The difference is mainly whether the mic is made specifically for spoken word or is capable of being used as a miniature microphone off the human body. Some models are water and sweat resistant and are useful for hiding in stage costumes and nearby props.
In choosing lavs for field video, it is important to match the type of mic to the kind of production your video crew typically does. This is why more expensive and capable lavs are used by professional crews encountering widely varying types of audio recording situations.
Finally, every video crew needs a shotgun microphone with shock and wind protection. This is the bread-and-butter microphone for most production recording. On or off a boom pole, shotguns are staples for every kind of sound pickup.
As with all microphones, there are wide choices of shotguns. What’s common is they all have a hyper-directional polar pattern with a condenser capsule, whether electret or true condenser. From this point on, they differ in capabilities and cost.
Lower-cost battery-operated electret condenser shotguns, though quite good in their functionality and sound quality, are subject to erratic noise and artifacts in poor weather conditions, such as extreme humidity or very cold weather.
True condenser mics, which are more expensive and require 48-volt phantom power to operate, are more robust in poor weather and are the choice of video crews who work in all environments.
Also important is the wind and shock protection. Wind and mic movement are the enemy of good sound and must be controlled. Professional protection gear, such as that made by Rycote, are essential accessories for shotgun microphones.
Most professional video crews use double-system sound recording on an outboard professional 32-bit float recorder or on recorders with 24-bit/48kHz capability. This sound is synced to the main video recorder’s scratch track. Again, the price and capabilities of audio recorders vary widely, from inexpensive Zoom models to high-end recorders by Sound Devices, Zaxcom and Aaton.
When a video crew has to record voice-overs or narration, a quiet space must be found. Being able to listen for good acoustics is another skill the sound operator must acquire. A large-diaphragm cardioid condenser microphone sounds best in such situations and handles lower frequencies well.
The most important trait for the sound recordist is to understand which type of mic works best in the given situation. This comes with experience. If the environment has a lot of ambient sound that can interfere with the clarity of a person’s voice, a cardioid or shotgun mic is the best choice. In acoustically poor environments, close miking with a dynamic is often best. There are no hard rules.
In live events with public address systems being used, use the most directional mike available to avoid bleed, feedback or room echoes. Keep the mics behind the loudspeakers. Live events with public speakers are different from concerts. Depending on the situation, it may be better to ask for an audio feed from the house sound system.
In some situations, noise gates, high pass filters and EQ can help make sound cleaner and more intelligible. Find the right threshold to use for processing to make your sound easier to understand. This is the kind of situation where mic placement is also critical.
If you are dealing with an inexperienced presenter, you might need to offer some coaching on how to use the microphone. If the speaker is behind a podium, make sure there is no movement from that position. If the speaker moves around and the sound is off-axis, it could kill the sound bite.
President Biden has a habit of randomly stepping away from the podium during speeches. For this reason, White House sound operators have given him a wireless handheld mic to use when moving. Take nothing for granted or you might lose the audio.
Wireless lavalier mics are important for walking interviews, weddings, public events or anywhere the subjects are in motion. Aesthetics alone make using a wireless mic a challenge. If necessary, make sure the mics are well hidden but are in range of the receiver for a good signal. Scope out the wireless frequencies in advance to avoid interference.
Low-cost 2.4 GHz wireless microphones sound fine when they work, but in crowded frequency enviroments they can be problematic. This is why more expensive and professional-level digital wireless models are best to use when the sound reliability is critical.
Location sound for video is made up of a constant set of challenges that change with every scene. It is important to know the best available tools for each situation. Though the basics of the equipment can be learned, only hands-on experience in the field puts that knowledge to the test.
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