hello! this blog in a work in progress, check back to see if i've figured out html yet!

Audio for virtual production

This page explores the unique sound recording challenges presented by virtual production!.

Audio

22/01/25

On a typical film set, location sound recording usually consists of as follows:

Scratch track: A temporary sound recording, intended to be replaced later. This is usually from a microphone on the camera, whether built-in, or something slightly better (I personally love the Boya BY-P4 for this use. It's a small omni-directional condenser microphone which is small enough to fit nicely on just about any camera, even my little Blackmagic pocket cinema camera, and provides a much better sound than most built-in microphones).

Dialogue Track: The main audio recording of the words spoken by the characters on screen. This is most often captured using a boom mic, but can also be a lavalier mic. A boom operator will position their mic usually above the actor that is speaking, to capture a clean take of the actors dialogue.

Wild Track: refers to any other sounds that are recorded on location, seperately from the main (dialogue) audio. This could be an off camera scream, footsteps, or anything else which was missed during a take.

Atmos: the atmospheric sounds captured on set. This could be the sound of rain, wind, russling trees, basically anything else that adds to the atmosphere of the scene.

Room Tone: ever noticed that 'silence' is never really silent? Unless you're chilling in an Anechoic chamber. There's always something in the background, a hum of a fridge, the whine of electricity, or the rhythmic whirring of a fan.

It's super important to capture an uninterrupted recording of these sounds for each location, for two main reasons. The first being, during editing, the sudden abcense of any sound can be very jarring, especially between camera cuts. Room tone can be used to cover up this abcense of sound creating better flow between shots.

The second reason is that it can be alot easier to remove an unwanted sound from a recording if you have a clean reference of it. Thanks to decicated audio editing software, such as RX11, offered by iZotope removing these unwanted sounds is possible, even without a room tone track, but it sure makes it alot easier!

When filming in a studio, it's obvious that alot of these sounds aren't available to record, so how do you build the atmosphere of a virtual world without being able to record these physical sounds? Well, That's where foley comes in!

Foley: describes sounds that are added in post production. This can be anything that couldn't be recorded on location. This video provides a great insight into the work of a foley artist, and how sounds aren't always what they would seem at first!

A scene recorded with a virtual production workflow relies heavily on foley to reproduce the sounds that would otherwise be captured on location. However, it's very import that the sounds used actually replicate the enviroment in which the sounds would have been recorded in. Many factors can change how a noise sounds, such as echo, reverb, distance and much more! Although these variations can be replicated with audio proccessing, its always better the attempt to capture the most fitting version of a sound in the first place. Imagine an actor walking through an empty warehouse, their footsteps would have a distinct echo to them, if this echo was missing from the reecording, you may not be able to instantly recognise it, but it would just feel slightly off.

A deepish-dive on microphones and mixers

Microphones come in all different shapes and sizes, and use a mulitude of different technolgies, for different use cases.

Shotgun mics: These microphones are most commonly associated with sound recording for film and TV. They're designed to capture sound at the end of the mic, and reject 'off-axis' sound from the sides. These mic's typically have a supercardiod polar pick-up pattern (this stuff's confusing, so I'll not go into it, lol). There's many different lenghths of shotguns, ranging from 'stubby's', like the Audio Technica At875r to 'rifles' like the Sennheiser MKH60. Generally, thee longer the microhphone, the narrower the pick-up will be. An easy way to think of this is it's just like the focal length of a camera lens, the more zoomed in, the less you will see!

Lav mics: A lavelier micrphoee, aslong reffered to as a 'clip-on', is a super small microphone, usually connected to a cable, which can get close to the source of a sound without being seen. These can be put just about anywhere, tapes to an actors chest, hidden behind objects in frame, or placed around somewhere no other microphones could be placed, like in a car during an explosive chase scene!

Condenser mics: These microphones are what you'll commonly see in a sound recording booth. They're usually omnidireectional, meaning they pick up sound from all angles, not practical when trying to pick out a specific sound, but in a controlled enviroment like a sound treated booth, this isn't a problem. These are especially good for recording vocals, as they provide the most accurate to life depiction of voice availible.

Audio Recorders: These too come in all different shapes sizes and abilities. Most commonly, a location sound recordist will use something like a 'Sound Devices MixPre-6 II' this ones peticuarly fancy, and is regarded as an industry standard device. The dfining factores for price of these devices include the number of inputs, quality of their preamplifiers, bit-rate and dynamic range.

When using something such as a lav mic however, plugging the mic straight into one of these, with a cable trailing meters from an actor, isn't always the most appropriate solution.

There's two main solutions to this problem, which can be used in conjuntion with eachother. The first being a super samll audio recorder, like the 'Tascam DR-10L' this can be place somewhere discreet, such as an actors back pocket, or strapped to their waist. Howeveer this doesn't offer a way for the audio to be monitored as it's recorded, this is where wireless solutions come into play.

Recently these have hit the consumer market, in the form of devices such as the 'Rode wireless GO', but historically have beeen reserved for higher budget productions, thanks to the high pricetags of devices offered by the likes of 'Lectrosonics'. The high prices of these devices are justified, as maintaining a stable high bit-rate radio broadcast is an engineering marvel. A location sound recordist is usually responsble for the set-up of these, and thanks to the ever-increasing amount of electronic devices spurting out their own radio frequencies, whether intentially or not, can make this a very difficult task.

23/01/25

Tips, Tricks & thing to think about:

Boom mics:

When using a shotgun mic, there’s rarely a reason to have it completely ‘naked’. You might aswell keep a foamie on it, as it gives it some extra wind protection during movement, and affects audio quality so negligably that it dosn’t really matter.

On the end of said foamie, its it’s a good idea to place a strip of brightly covered tape on the end of it, this makes it much easier to spot when it has dropped into frame, especially against a black background.

Internally cabled boom poles are expensive, and most of the time, not a great investment. Many of them _____ from cable noise as the internal cable moves around. A better, and cheaper solution is to wrap the cable around the outside of the pole. Even better, use a thick coiled cable such as this one , these are a lot more forgiving regarding their placement around the pole, as a straight cable will slacken on once the pole is extended, and become troublesome.

A trick to counter cable slackness is to take two pieces of electrical tape, tape them together and make a tight loop around the pole - you might want to do this at a few intervals down the length of a pole. A tension straps works better a a permantant solution, but in a pinch, leccy tape works great!

Booming a mic for hours on end can be super annoying, aswell as terrible for your shoulders. There’s many ergonomic solution for this, such as hip supports and counterweights, but anytime it’s possible, you might aswell boom from below. Of course its always best to boom from about with the mic point at the subjects chest (just past the mouth to cut down on unwanted polosives) but on. A long day of shooting, destroying your body for an ever so slightly better sound just isn’t worth it. -this tip is a bit more ____ to documentary and to shooting rather than for film , but still useful. Of course at any chance you get you should opt to use a boom stand, rather than being the sound equivalent of a human tripod!

If your starting out in sound recording, if you have the funds, a sennheisser mk416 is probably the best investment you could make. As much as location sound recordists these days will opt to only use this mic as an outdoor microphone, it can be used for just about any ____. Another mic I really enjoy using is the sennheiser K6, if you can manage to find a complete kit, it offers great versatility, having three different modules, a ____, ____,and _____ capsule.

Blimps and dead cats: Using a dead cat inside will make any experienced sound recordist gag, theres usually absolutely no reason for it, if theres no wind, you dont need wind protection! The same goes for the blimp, leaving it on leads to less sound wave hitting the capsule, therefore forcing you to turn up the gain on the recorder, creating a higher noise floor. Off course sometimes it’s worth leaving the main component of the blimp on the mic, to further _____ off-axis nose reduction but you should at least take off the front component of the blimp.

Lav mics: A clip-on microphone is usually the best possible sound you can capture, as it;’s the closest you can get to the source of the noise, however they’re probably the most finicky and problematic -for many reasons- option.

No matter what, you’ll likely always have to battle either wind noise, rustling from clothing or raspy breathers. Luckily, there’s a world of options to help combat this!

First of, theres the foamie, this can be a life saver for mixing a raspy breather, such as someone suffering from asthma, as it helps kit the wind noise from their breaths.

Next up is a ‘dead mouse’, these work great to combat wind noise, however look ugly, and the director of a shoot will never opt to have this on show. Of course, there is circumstances where this is unavoible, such as on top of a windy mountain. There is other options though! Fake brche’s and pins can work great for this, aswell as specialised solutions such as _this_ clip, which will help to cut noise while being completely hidden!

Clip mic placement: theres an endless amount of solutions to attach a lav to someone rather than just using a clip _stickies n all that—

check Reddit-.

However, it’s important to respect people boundaries when hoping to mic them up! Always start by asking if someone is comfortable for you to do so, or if they’re happy to do so themselves. It’s important to always remember to never touch someone without their consent! - in general, not just on set!

.

Navigation
Section

Latest Updates:

  • 22/01/25
  • Section