Object Audio - whats all the noise about


Bruce Devlin TV-Bay Magazine
Read ezine online

We all know that getting the audio right makes the pictures better. Anyone who has seen a movie created for Object Audio like Dolby Atmos will know that there is something special about it. To figure out what that is, let's rewind a little and see why we might need it.

Remember the good old days of mono audio on TV? Mono audio gives a single channel of sound played back through one or more speakers. That's fine for many genres, but to increase the feeling of being in the scene, stereo audio was introduced, so that left and right channels are transmitted, giving our ears the ability to hear sound moving on either side of us like we do in real life while we watch the images.

With the advent of cheaper electronics, we moved to a surround sound system where we added more speakers to give the impression that sounds could come from in front and behind as, as well as either side of us. Typically, today these surround sound systems use 5.1 channels. This means that we have 5 full bandwidth channels:

  • Left Front
  • Center
  • Right Front
  • Left Rear
  • Right Rear

And one low bandwidth channel (this it the ".1")

  • Low Frequency Effects (LFE)

This system essentially takes a sound mix from the program creator that is mastered on 5.1 speakers and then maps it on to the 5.1 speakers in your home or in the theater.

Audio processing technology is now very cheap your cellphone can do more audio processing than dedicated hardware from the 1990s. We have much bigger screens today, and with the rollout of UHD, it is likely that we will be sitting even closer to them. To increase the sense of "being there," adding a vertical element to the sound can make a dramatic difference.

It is impractical to move from a situation where we have six fixed speakers to one where we have hundreds of speakers that position the sound exactly, especially when most of the time there will be little or no sound coming from an individual speaker. Imagine instead a "bed" of audio that is the traditional stereo, or 5.1, mix that you add effects or objects to with an audio stream and some control metadata.

In its simplest form, the UK's audio description service does just that. Start with a stereo "bed" that is the normal program mix and then add a description for the visually impaired and a control track that adjusts the volume and position (left-right pan) so that a smart decoder can mix the sound together.

A full cinematic system is very similar, but with more objects and more metadata. Each cinema may have a different number and position of speakers depending on budgets. The object sound system provides the "bed" of audio that is mapped onto the speakers in the theater. Each object sound is then mapped to one or more physical speakers at the right time and the right volume to provide very specific spatial effects for the audience.

Knowing these basics, you can see how this system might map to a consumer setup where there will be fewer speakers, but by calibrating the room, a sound processor could do a good job of mixing the sound between spatial speakers and upward firing speakers to give a pretty good approximation to the 3D sound experience in the cinema.

Currently, we send our content to the listening / viewing environment in a fairly linear way. The mix that is created at the content provider is the mix heard / seen by the viewer. Technologies like IMF are enabling content creators to produce and distribute versions more cheaply. Technologies like object sound with consumer audio processing units allows different objects like languages, high dynamic range effects (for quiet environments) and low dynamic range effects (for noisy environments) to be selected and / or mixed at the receiving point. We're increasingly moving from a linear "here's my content" world to a component "which bits of the content will give you the best experiences world. It's a fun time to be in technology.


Tags: iss111 | object audio | dalet | mxf | Bruce Devlin
Contributing Author Bruce Devlin

Read this article in the tv-bay digital magazine
Article Copyright tv-bay limited. All trademarks recognised.
Reproduction of the content strictly prohibited without written consent.

Related Interviews
  • Dalet at NAB 2016

    Dalet at NAB 2016

  • Dalet at IBC 2015

    Dalet at IBC 2015

  • DALET ACADEMY NAB 2015

    DALET ACADEMY NAB 2015

  • DALET SportsPack at NAB 2015

    DALET SportsPack at NAB 2015

  • Dalet at IBC 2014

    Dalet at IBC 2014

  • Dalet at NAB 2014

    Dalet at NAB 2014

  • Dalet at IBC 2013

    Dalet at IBC 2013

  • Dalet at NAB 2013

    Dalet at NAB 2013

  • Dalet at NAB 2012

    Dalet at NAB 2012

  • NuGen Audio at IBC 2013

    NuGen Audio at IBC 2013

  • Arkivum at BVE 2012

    Arkivum at BVE 2012


Articles
The way forward in a changing world
Alan Wheable The broadcast and media industries are evolving in all areas to adapt to the challenges of competition from OTT, changing user viewing habits, technological advances in image resolution, dynamic range and colour rendition as well as embracing new video over IP infrastructures.
Tags: iss136 | omnitek | aims | ip | smpte | 2110 | 4k qc | ultra xr | nmos | ultra tq | Alan Wheable
Contributing Author Alan Wheable Click to read or download PDF
BSC Expo 2019 Report
Paul MacKenzie BSC Expo returned to the Battersea Evolution on Friday February 1st and Saturday 2nd. It is a busy and friendly event though this year in need of some temperature control: exhibitors around the entrance area were uncomfortably aware of the wintry conditions outside and the main hall was in need of cooling.
Tags: iss136 | bsc | cinematography | canon | c700 | c200 | cartoni | holdan | blackmagic | peli | panasonic | sennheiser | sony | fs5 | teradek | viten | flowtech | Paul MacKenzie
Contributing Author Paul MacKenzie Click to read or download PDF
Flexible Connectivity Hits Europe
Yvonne Monterroso The low-latency Dejero CellSat network was launched in Europe in January of 2019, which is excellent news for European broadcasters who can now benefit from the same flexibility CellSat provides North American Dejero customers, such as World Racing Group (WRG).
Tags: iss136 | dejero | wrg | cellsat | ku sat | is-35e | cellular | Yvonne Monterroso
Contributing Author Yvonne Monterroso Click to read or download PDF
Keeping Your Post Prodction on Track with Subclips and Search Bins
Alex Macleod

For my 2nd Kit Plus article I thought I’d try and build on the theme of my first, and that’s one of making sure things are organised at all levels of your post production projects.

Last time I talked about trying as best as you can to stick to the ‘two week rule’, making sure that the names & locations of every asset you import, and every bin & sequence that you create in your project - will make sense to you regardless of how long it is you spend away from it.

Tags: iss136 | mediacity training | subclip | premiere pro | gvs | bve | bve2019 | Alex Macleod
Contributing Author Alex Macleod Click to read or download PDF
Sennheiser Memory Mic User Review
Dr Anthony Willman The Sennheiser Memory mic, adding to the new generation of semi-professional equipment that is helping the need for high quality audio in parallel markets that until now, did not have the budgets to achieve ‘great’ results.
Tags: iss136 | sennheiser | memory mic | doctor | audio recorder | Dr Anthony Willman
Contributing Author Dr Anthony Willman Click to read or download PDF