Audio Post Production Demystified: A Comprehensive Guide For Filmmakers (Part 3)

Welcome to part 3 of Audio Post Production Demystified. You can find part 1 here and part 2 here. The media industry is fast paced and ever changing. Here at 344 Audio we are dedicated to keeping up with all of the latest trends and guiding filmmakers through our process. Join us in exploring some of the most highly anticipated emerging audio technologies used today. As an added bonus, we have provided a Language Glossary for our readers.

Emerging Technologies

Immersive Audio Format - Dolby Atmos

So, you are probably wondering, whats the next big step in film sound? We have 4K cinema projection, IMAX, 8K cameras, what has changed in audio?

One of the most exciting emerging technologies in film sound, comes from industry innovators Dolby. Dolby Atmos is a multichannel format that expands on the capabilities of 5.1 and 7.1 surround sound by offering additional speakers (up to 64 speakers in total) with some speakers being placed above the viewer. It also offers object based panning, which means that complex movements are no longer limited by the amount of speaker channels in a system.

The panning data of a sound is more specific and has a higher resolution when more speakers are employed in the playback system. This can create really dynamic and clear mixes with plenty of options to separate elements, as well as provide an immersive experience for viewers.

Other immersive audio formats are being used in 360 video, which employ object based panning, or ambisonics.

Speech Synthesis Technology - Adobe Voco

Adobe were met with considerable criticism and concern when they revealed Voco, a Speech Synthesis Technology that is working towards being indistinguishable from real human voices.

It works by recording at least 20 minutes of a Voice Actors speech, and can then generate phonemes from the resulting material, even some that were not present in the recordings.

The implications of this ethically are concerning to some, but it could mean that one day ADR Recording will become a thing of the past. Voice Actors would simply record their 20 minute's for various accents and dialects, and then license this to Producers for use in a film.

Virtual Microphone System - Slate Digital VMS

Audio software plugin developers Slate Digital, introduced their latest groundbreaking technology recently - Slate Digital VMS.

This hardware/software combination uses an extremely transparent microphone and a sonically neutral preamplifier to capture signals and then process them in to order to replicate some of the industry's most revered modern and classic microphones.

The reason that this technology is so exciting, is that it allows the user to change the virtual microphone after recording, offering much more flexibility to alter the tone of a voice performance in the mix.

Advanced Sound Design Tools - Krotos Audio

Krotos Audio are Edinburgh based software developers known for their forward thinking approach to Sound Design tools.

Boldly going where no one else will go, they have created two profucts which have changed the way that we create and implement Sound Design.

Their first product, Dehumaniser, has taken the industry by storm. It gives Sound Designers a much more intuitive and direct approach to designing creature and character vocalisations. It was used in the recent live action adaptation of Jungle Book and many other films and games. Dehumaniser offers a multi step process which shapes the performance of a Voice Actor in the studio. This allows their live performance to sound like an animal or monster..

Their second product, Reformer, allows users to speak or perform foley into a microphone, and trigger specific sounds. For example, we can speak into a microphone and generate random alarm sounds, tap on the floor to create the sounds of a walking Tiger or even bend some plastic to create flesh ripping seffects.

Smart Mixing Tools - Izotope Neutron

Izotope are a household name in the world of sound for film. Their industry leading RX software controls and reduces unwanted artefacts and noisy audio.

Their latest venture however, is also a game changer. Neutron is a smart mixing tool that can help balance audio tracks intelligently, and save some time on fast turnaround projects. It uses multiple tools which analyse incoming audio and apply changes throughout the Final Mix.

Particles Based Sound Design - Sound Particles

Another product that has both surprised and excited the film sound community in recent years is Sound Particles.

This software allows for the use of 'particles', a CGI like system which can generate thousands of sounds and place them in a 3D space, capturing them through a user defined set of virtual microphones to increase the realism and extend the usefulness.

Common uses for this include battlefield scenes, where Sound Designers spend days crafting sound assets to immerse and excite the viewer. Sound Particles can take gunshot, vehicle and vocal recordings of your choice, randomise them and spread them across the sound stage, in much less time than it takes to execute this manually.

Virtual Foley Instruments

There are now 'Virtual Foley' softwares available, which allow Foley to be performed using a MIDI keyboard to trigger footstep sounds against the picture. The performer plays keys on the keyboard while the software cycles though tens of versions of footsteps for each shoe and surface type needed.

Although this software can be useful, it does not quite replicate the flow and artistry of a recorded Foley performance.

Language Glossary

Audio Effects & Processing

Equaliser (EQ) - An audio effect which attenuates or increases user defined frequencies.

High Pass/Low Cut Filter - An audio effect that attenuates all frequencies below a user defined frequency cutoff point.

Low Pass / High Cut Filter - An audio effect that attenuates all frequencies above a user defined frequency cutoff point.

Compressor - An audio effect that reduces the dynamic range of a signal.

Expander - An audio effect that increases the dynamic range of a signal.

Gate - An audio effect that mutes the signal once it's level falls below a certain threshold.

Reverb - An audio effect that simulates the reflective sounds of a room or space.

Delay - An audio effect that duplicates a signal and then delays it to create echo effects.

Chorus - An audio effect that uses multiple delays and offsets them by varying degrees to simulate a vocal chorus.

Phasing - An audio effect that uses a duplicate version of a signal with a variable phase shift to create movement.

Flanger - An audio effect that duplicates a signal and delays it by a small increment to create a metallic texture.

Time Compression/Expansion - A process in which audio is stretched or shortened without changing in pitch.

Pitch Shift - An process which changes the pitch of a signal.

Panning - An audio effect where the signal moves around the stereo field.

Noise Reduction - An audio effect that can aid in reducing noise, clicks, pops, breaths and other unwanted sounds within a signal.

Dry - An audio signal before processing.

Wet - An audio signal after processing.

Oscillator - A device that generates an audio waveform, usually used for sound design in synthesizers or for testing audio devices.

Output - The location where a signal leaves the device.

Input - The location where a signal enters the device.

Amplify - Increase the level of a signal.

Attenuate - Decrease the level of a signal.

The Perception of Sound

Psychoacoustics - The science behind the perception of sound.

Doppler Effect - A psychoacoustical phenomena in which a sound appears to change in pitch as it moves past the listener at high speeds.

Haas Effect - A psychoacoustical phenomena in which two duplicate signals are only perceived as independent from one another when delayed by >30 ms or amplified by >10dB.

Masking - A psychoacoustical phenomena in which louder sounds affect the clarity of quieter sounds within the same frequency band.

Threshold Of Pain - The level at which sound can become painful to humans, generally accepted to be 120dB SPL.

Threshold Of Hearing - The level at which sound can become audible to humans, generally accepted to be 0dB SPL.

The Quality of Sound

Frequency (Hz) - The number of times a waveform cycles per second. This can be measured in Hertz.

Decibel (dB) - A logarithmic scale for the relative measurement of a sound's intensity level.

Volume - A non technical term that usually refers to the SPL of a signal.

Loudness - A term used to describe the perceived intensity of a signal, which is usually subjective. Loudness can be measured in Loudness Units (LUFS) or Sound Pressure Level (SPL).

Gain - A parameter which alters the input level of an audio device.

Headroom - The difference between the peak and average level (RMS) of an audio waveform.

Normalise - To adjust the level of a signal so that it's highest peak is at a user defined level.

Frequency Range - The range of frequencies in which an electronic device is useful.

Dynamic Range - The difference between the highest and lowest signal level in an audio waveform.

Signal To Noise Ratio - The ratio in level between desirable audio (signal) and undesirable audio (noise) within a recording.

Noise Floor - The level of noise below the desired signal level. This can be measured in Decibels (dB).

Bit Depth - The resolution of an audio signal, measured by the amount of bits per sample.

Sample Rate (kHz) - The number of samples an audio signal carries per second.

Mono Recording - An audio file which has been recorded with a single microphone.

Stereo Recording - An audio file which has been recorded with two or more microphones.

In Sync - An objective measurement made by the Sound Team which shows that two audio waveforms align correctly.

Out Of Sync - An objective measurement made by the Sound Team which shows that two audio waveforms do not align correctly.

Analogue Signal - A smooth continuous waveform with infinite set of values.

Digital Signal - A waveform with steps and a finite set of values.

Phase Cancellation - An audio discrepancy caused by a duplicated signal being phase inverted (waveform being turned upside down) which can attenuate the signal level completely.

Feedback - An audio discrepancy caused by a signal being recorded and reproduced in close proximity, which can cause loud distorted sounds.

Clipping - A distortion caused by recording or exporting audio above the systems capable level. The upper limits of the waveform will be squared off.

Resonant Peak - An audio discrepancy caused by a narrow range of frequencies that are much more prominent in a signal.

White Noise - An audio discrepancy caused by using inferior recording equipment.

Hum/Rumble - An audio discrepancy caused by the presence of electrical equipment in close proximity to the microphone when recording.

Click - An audio discrepancy that occurs when an unwanted transient is present in an audio waveform.

Pop - An audio dependency that occurs when plosives (P, B) are used in speech and the microphone is not appropriately protected.

Other

Overdubbing - The process of layering recordings together through multiple performances.

WAVE File (.wav) - an uncompressed audio file format that can carry extensive metadata. The BWF variation can carry additional data such as time stamps.

Audio Interchangeable Format File (.aiff) - An uncompressed audio file format created by Apple.

MP3 File (.mp3) - A compressed audio file format widely used in music.

Advanced Audio Coding File (.aac) - A compressed audio file format commonly attached to compressed video files.

Phantom Power - A system used to supply condenser microphones with operating power, negating the need for external power supplies.

Tweeter - The part of a speaker that reproduces high frequencies.

Woofer - The part of a speaker that reproduces low frequencies.

Automation - A process in which a DAW can adjust user defined parameters whilst the mix plays.

Beats Per Minute (BPM) - A steady clock which represents the perceived speed of a music track.

Condenser Microphone - A microphone powered by 48V Phantom Power.

Dynamic Microphone - A microphone powered by the movement of air.

Congratulations, you have now completed all three parts of our comprehensive guide to Audio Post Production. If you are looking for a refresher on Job Roles or Workflow in Audio Post, check out Part 1 and Part 2 of this series. Let us know what you want to read about next!

If you enjoyed this article please check out our ultimate guide to audio post- production: https://www.344audio.com/post/the-ultimate-guide-to-audio-post-production-sound-design