AoIP in the intercom world


John Sparrow TV-Bay Magazine
Read ezine online

Everyones talking about using AoIP (Audio over IP) in the broadcast world, but what does it mean to the operators actually making the production - the intercom users? And after years of interoperability taking the lowest common format of analogue tie-lines (also known as 4-wires), has intercom today already moved into the digital world by sharing digital audio resources with other types of hardware?

Until recently there were several standards for transporting digital audio between hardware; some of them common to the manufacturers, some standard amongst a number of different manufacturers and some just totally bespoke. Todays standardisation on Dante and AES67 helps simplify matters, but how?

Interoperability has always been part of the intercom world; analogue 2-wire beltpacks allowed different areas to work together over microphone cables or tie-lines, as an early example. Then the intercom world explored the benefits of telephony to interconnect operators across sites and even countries using POTS (analogue telephony). This was basically extending 4-wires across telephone copper cables - it was expensive and had balance issues resulting in feedback of your own voice, but it worked sufficiently well. Add simple GPIOs (general purpose interfaces, contact closures etc.) and you had some basic signalling between intercom systems. Digital Intercom had to use multiple lines to carry both voice routing and signalling data - anyone remember voice over data modems?

When ISDN came along the digital interconnection started to become much easier to manage, and ISDN interfaces for everything audio became the fashionable item to have. It was still costly, and the ISDN lines often had to be booked in advance, but it worked in a similar way to POTS, just with embedded data and caller ID.

Within the studio complex MADI grew to be the digital audio interface of choice, allowing multiple streams of AES3 audio from, for example, a sound desk mix-minus bus to the intercom system over a single cable, rather than 64 pairs of analogue 4-wires. MADI (AES10) worked well between devices and was effectively the forerunner of todays AoIP communications.

Early adopters in IP connectivity from a manufacturing point of view include Trilogy Communications, which launched the worlds first IP connected intercom in 2002. The system used standards-based IP networks to allow intercommunication between intercom matrices, which permitted Trilogy to install several hundred systems world-wide that were all interconnected. At this early stage intercom bandwidth was controlled by the use of compression codecs; in this case G.722 was the best one that could be used, with an audio bandwidth of around 7.5kHz, which has since been proven to be adequate for talkback needs.

Advances in technology saw the introduction of IP connectivity of the intercom panel, again using standards-based IP networks. This meant that panels could be sited anywhere within the Wide Area Network and put more and more onus on the IT engineers rather than broadcast engineers, which was an issue in itself. Most IP panel connections shunned compression of the audio to achieve lower latency, since its no good telling a cameraman to switch shots and having the intercom arrive some seconds too late! IP panels were also fighting for bandwidth with other uses of the IP network, be it an office network or something also serving video, so we were introduced to the world of VPNs.

Various interoperability Audio over IP standards started to appear, and the joys of a plug-fest where different manufacturers joined their hardware together to test interoperability became fashionable. The EBU worked first on video interoperability then proceeded to work on audio interoperability between intercom manufacturers. Differing standards included Ravenna, AVB and Dante, all fighting to be the technology to use as a joiner between disparate audio systems. It was obvious that a single standard was needed and various groups were working together to achieve something that we knew would just be plug and play.

The common technology below all these standards is AES67 with more sophistication built above it, like discovery and routing within the higher standards like Audinates Dante¢. This base level makes AES67 the AoIP choice, certainly between devices within a contained system such as between end-points within a single manufacturers system, where discovery and clocking is provided by the system.

Dantes rapid acceptance within the live event and performance communities meant that this was the choice for Clear-Com when providing simple connectivity to music consoles, public address and other intercom systems.

The advantages of using IP to interconnect different audio devices include being able to leverage existing IT equipment with their diagnostics capabilities, and also use the legions of trained IT engineers - although this has brought its own problems in terms of training them to respect the differences between audio and video media. It is perhaps more important that the audio (or video) contained within an IP packet arrives quickly and without delay than the message sent to a printer in an office!

So, things like QoS (quality of service) and the network resilience with multiple alternate routes have become important, and the industry has created such things as spine and leaf network layouts to provide for redundant connections with a layer of control software to ensure it all works.

AES67, with further refinements on technical options, clocking and discovery, is the common standard for audio and intercom over IP, especially within broadcast operations. For our customers, the ability to link multiple manufacturers boxes together and share multi-channel programme audio with ease, and to monitor its routing and diagnostics using easily available IT tools, is releasing broadcasters from the complexities of standards conversion and hardware patching and monitoring. For these reasons, the march toward the adoption of AES67 is well under way and I would expect to see many examples of this claim this year.

AES67 (via Dante) also allows large intercom systems to be connected offering scalable, future-proof solutions for the production staff to utilise to their advantage. Intercom has always had to play its part in being interoperable with audio systems and a common standard like AES67 is only going to help everyone communicate better, more quickly and at a higher quality than ever before.


Tags: iss128 | clearcom | clear-com | dante | aes67 | beltpack | isdn | John Sparrow
Contributing Author John Sparrow

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
  • 32 Keypanel Intercoms from Clearcom at NAB 2017

    32 Keypanel Intercoms from Clearcom at NAB 2017

  • CLEARCOM LQ SYSTEM at NAB 2015

    CLEARCOM LQ SYSTEM at NAB 2015

  • CLEARCOM FREESPEAK at NAB 2015

    CLEARCOM FREESPEAK at NAB 2015

  • CLEARCOM IOS INTERCOM at NAB 2015

    CLEARCOM IOS INTERCOM at NAB 2015

  • Clearcom at IBC 2012

    Clearcom at IBC 2012

  • JVC at BVE North 2011

    JVC at BVE North 2011

  • Intercom over AES67 with V-Series IRIS from Clear-Com at IBC 2018

    Intercom over AES67 with V-Series IRIS from Clear-Com at IBC 2018

  • Clear-Com adds Freespeak Edge 5Ghz 8ch and configurable at IBC 2019

    Clear-Com adds Freespeak Edge 5Ghz 8ch and configurable at IBC 2019

  • Clear-Com Free Speak II IP Transceiver at IBC 2018

    Clear-Com Free Speak II IP Transceiver at IBC 2018

  • Clear-Com E-IPA Card for Eclipse HX Digital Matrix at NAB 2018

    Clear-Com E-IPA Card for Eclipse HX Digital Matrix at NAB 2018

  • Virtual Panel on Apple watch from Clear-Com at NAB 2018

    Virtual Panel on Apple watch from Clear-Com at NAB 2018

  • Mobile comms from Clear-Com with LQV4 software and Agent-IC shown at BVE 2018

    Mobile comms from Clear-Com with LQV4 software and Agent-IC shown at BVE 2018

  • Clear-Com HelixNet at NAB 2016

    Clear-Com HelixNet at NAB 2016

  • Clear-Com FreeSpeak II at NAB 2016

    Clear-Com FreeSpeak II at NAB 2016

  • Clear-Com at IBC 2015

    Clear-Com at IBC 2015

  • Clear-Com LinQ at IBC 2014

    Clear-Com LinQ at IBC 2014

  • Clear-Com FreeSpeak II at IBC 2014

    Clear-Com FreeSpeak II at IBC 2014

  • Clear-Com ProGrid at NAB 2014

    Clear-Com ProGrid at NAB 2014

  • Clear-Com HelixNet Partyline at NAB 2014

    Clear-Com HelixNet Partyline at NAB 2014

  • Clear-Com: Concert at NAB 2013

    Clear-Com: Concert at NAB 2013

  • Clear-Com Eclipse HX at NAB 2013

    Clear-Com Eclipse HX at NAB 2013

  • Clear-Com: HelixNet Partyline at NAB 2013

    Clear-Com: HelixNet Partyline at NAB 2013

  • Clear-Com: Tempest at NAB 2013

    Clear-Com: Tempest at NAB 2013

  • Clear-Com Tempest at NAB 2012

    Clear-Com Tempest at NAB 2012

  • Clear-Com Eclipse MADI Card at NAB 2012

    Clear-Com Eclipse MADI Card at NAB 2012

  • Clear-Com Eclipse at NAB 2012

    Clear-Com Eclipse at NAB 2012

  • Clear-Com HelixNet Partyline at NAB 2012

    Clear-Com HelixNet Partyline at NAB 2012

  • Clear-Com at IBC2011

    Clear-Com at IBC2011

  • AES3 to Dante / AES67 converters from Glensound at NAB 2019

    AES3 to Dante / AES67 converters from Glensound at NAB 2019

  • Glensound Beatrice Dante Intercom at ISE 2019

    Glensound Beatrice Dante Intercom at ISE 2019

  • Glensound Anthens 2 Dante Turntable Pre-Amplifier at ISE 2019

    Glensound Anthens 2 Dante Turntable Pre-Amplifier at ISE 2019

  • SSL Dante AoIP with System T from Solid State Logic at IBC2019

    SSL Dante AoIP with System T from Solid State Logic at IBC2019

  • Glensound Dante Intercom System at IBC 2017

    Glensound Dante Intercom System at IBC 2017

  • Glensound Dante at IBC 2014

    Glensound Dante at IBC 2014

  • Virgil OB headphone amplifier from Glensound at NAB 2018

    Virgil OB headphone amplifier from Glensound at NAB 2018

  • Live Sports Broadcast Commentator from Glensound at NAB 2017

    Live Sports Broadcast Commentator from Glensound at NAB 2017

  • Glensound at IBC 2016

    Glensound at IBC 2016

  • Glensound at NAB 2016

    Glensound at NAB 2016

  • Glensound show Beatrice the AES67 Network audio intercom beltpack at IBC 2018

    Glensound show Beatrice the AES67 Network audio intercom beltpack at IBC 2018

  • PARADISO Lite commentary unit from Glensound at BVE 2018

    PARADISO Lite commentary unit from Glensound at BVE 2018

  • RTS at BVE 2017

    RTS at BVE 2017

  • RTS Telex at IBC2011

    RTS Telex at IBC2011


Related Shows
  • Bubble and Squeak Live and Loud: BVE Day 3

    Bubble and Squeak Live and Loud: BVE Day 3


Articles
Increasing Diversity in the UK Indie Market
Sam Addo

London director Sam Addo tells us more about how he aims to change the status quo when it comes to onscreen diversity with his new feature, Cards on the Table.

“Over the past thirty years, filmmakers have made movies telling a wide range of stories, however, in my humble opinion, those with disabilities, from the LGBTQ+ community and or those from ethnic minorities remain underrepresented on screen. For example, it is rare to find a film where the lead character has a disabil ity, and that underrepresentation is worrying.”

Tags: iss139 | cards on the table | feature | diversity | blackmagic | ursa mini pro 4.6k | lut | davinci resolve | Sam Addo
Contributing Author Sam Addo Click to read or download PDF
The Making of Zero
Keith and David Lynch

The Brothers Lynch explain how they created the sinister atmospheric world for their new sci-fi short

In a post-apocalyptic world where humankind has emerged victorious in a war against artificial intelligent machines, a young girl dares to venture into the unknown. This is Zero, the new sci-fi short film from acclaimed British writer-director duo The Brothers Lynch which has premiered at the Tribeca Film Festival.

Tags: iss139 | blackmagic design | davinci resolve | editing | grading | grade | mk2 zeiss | superspeeds | cinema 4d | molinaire | Keith and David Lynch
Contributing Author Keith and David Lynch Click to read or download PDF
Keeping Pace with the Content Revolution
Kevin Fitzgerald These are uniquely challenging times for broadcasters and their technical teams. Not only are they having to negotiate the move to IP-based infrastructures and the introduction of new formats and techniques such as 4K and HDR, they are also having to generate more content than ever before to support OTT and web services as well as traditional linear broadcast.
Tags: iss139 | streamstar | streaming | case 800 | ipx | ipx-3g | Kevin Fitzgerald
Contributing Author Kevin Fitzgerald Click to read or download PDF
State of the Nation - Getting Connected
Dick Hobbs - new We are all familiar with statistics about the growth of the internet. Cisco’s latest report, for instance, says that global IP traffic is increasing at 26% a year, and will reach 4.8 zetabytes a year by 2022. The number of connected devices will be three times the world’s population by the same date.
Tags: iss139 | cisco | kth | clickclean | ibc | Dick Hobbs - new
Contributing Author Dick Hobbs - new Click to read or download PDF
Original KVM or KVM over IP
Jochen Bauer Will the technology used in broadcasting solely consist of IP devices? For years, IP has been entering all areas of life. Especially control room applications as they are typically deployed in broadcasting benefit from the IP revolution in many ways. But an “IP-only broadcast world” is not yet here. Nevertheless, the trend clearly moves towards IP transmission, even though a large part of content production still uses traditional transmission paths. And therefore we continue to live in a hybrid world, using both original and IP-based technology. KVM experts Guntermann und Drunck still rely on both original KVM and KVM-over-IP™ to be able to offer their customers the best of both worlds.
Tags: iss139 | kvm | gdsys | guntermann and drunck | kvm-over-ip | Jochen Bauer
Contributing Author Jochen Bauer Click to read or download PDF