The Basics of Audio Equipment for Filmmakers

By Thomas Popp

In order to be a well-rounded audio engineer, it is crucial that you understand the tools available to you. I would like to begin by breaking down the audio equipment available and teach you their purpose, limitations, and some tips on learning how high quality audio is recorded. A good place to start is with an introduction to wireless systems.

A wireless system is a piece of equipment that allows you to take a sound source (microphone) and send the audio wirelessly through the air to a receiver instead of physically tethering that source microphone to its destination (a mixing console) with a cable. The benefit of wireless technology is that it allows the sound engineer to capture a source of audio that may not have been attainable in the past. We use wireless systems on talent when we are not able to get a boom microphone in the shot as well as to occasionally plant a microphone that will allow us to get a better ambience in a scene.

One of the debates that I always get when working on jobs is the highly opinionated question of WHEN to use them. On many productions, I receive phone calls from coordinators or producers that will begin right away by telling me how many wireless systems I need before they even begin discussing the details of the shoot. Even though I always take this information into consideration, it is very important as the sound mixer on a job to fully understand the details of the shoot you are working on – not just how many wires.

Producers may understand the sound process, but may not fully understand the equipment requirements for the job. A great example of this would be a job that I worked on that required me to bring eight wireless systems to wire talent. After discussing the shoot in more detail, I learned that there were indeed eight talent in the shoot, but they were NOT going to be there at the same time! Had I not backtracked and asked my employer for more details, I would have had to charge them for additional wireless systems that would not have been needed. Instead, I brought a basic package with two wireless systems and a boom and never even brought the wireless out; the boom happened to be my best option for capturing sound on that particular job.

Zaxcom TRX900LA Digital Recording Wireless Transmitter

It is still important to know when it is required to use a wireless system and when it is not. The main thing to consider when deciding to use a lavalier is whether or not the audio matches the camera perspective. Camera perspective is very important in order to make sure that your audio matches the framing of video. We have all seen videos on YouTube that were made with smart phones as well as DSLR cameras using the internal microphones built into the camera. If you listen to the audio, it will sound extremely distant and very noisy. This happens because the ambient noise apparent in the room is so prevalent that it can take precedence over the actual source of audio you are trying to capture. Unlike our ears, which are subconsciously told by our brains to cancel and filter out noises while focusing on the voice of an individual, a microphone instead captures everything it hears (even if it means the main focus of the video is overshadowed by the sounds of traffic or even a fan in the room). However, due to the directionality of certain microphones, the patterns of how they capture audio can help to deviate extraneous sound that is not the primary focus.

Wireless systems and lavaliers are important in keeping consistent sound tracks when working on productions like, but not limited to, documentaries, reality shows, and multi-camera television/film productions. An ENG Sound Mixer or Boom Operator may run into difficulties if there are multiple cameras with varying frame lines, lighting difficulties due to staged or practical lighting, and noisy locations which can greatly diminish the probability of getting a clean and usable audio track. If you are not able to get consistent audio with a boom on these types of gigs, it may be beneficial for you to use a lavalier that will allow you to have a consistent audio track for each person that is wired.

Interference and audio dropouts are another factor to consider when using wireless systems and can be a sound mixer’s worst nightmare. Make sure you read and fully understand the manual that comes with your wireless system in order to learn how to scan and select frequencies that are clear and open in your location. Without doing this fundamental step, you can run into situations where the wireless may sound perfect and have optimal range, only to find out that ten minutes before you are required to roll, something has since been turned on that wasn’t before, and is now interfering with the wireless frequencies you selected! Always complete this “Final Check” right before you are ready to go!

In the next blog post, I will be talking more about the process of wiring talent as well as set etiquette of an ENG sound mixer.

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Thomas Popp is the owner of Video Mantis Inc and Popp Sound, LLC. He has been mixing sound for film and television for 15 years and has also been a guest speaker for Hurlbut Visuals during their DSLR Boot Camp events. His interactive E-book, entitled Down to the Wire, aims at giving enthusiasts a go-to reference guide to learn set etiquette and wiring techniques to capture high quality audio on set. It is available now for iPad, and will be available for both iOS and Android platforms soon.