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Analogue still crashing digital and IP’s intercom party

AVB, IP, OCA and digital and networking in general are dominating the ever more critical world of intercom and communications. But is this the only show in town?

Look at just about any technology area today and the feeling is new digital technologies are sweeping away everything that went before. This seems to be the case with intercom, where digital IP and Ethernet-based distribution are seen as the way ahead for communications in broadcasting, live sound, theatre and general venue installation. But, as has happened so often in technological history, the old techniques are not supplanted completely but carry on almost in the background, continuing to be used because they still have something to offer that their supposed successors do not.

Old established intercom technologies – such as two and four-wire party line systems – are still with us but the overwhelming focus now is on new means of carrying multiple signals to cover large areas, linking many staff over a sophisticated network. Both NAB and Prolight+Sound highlighted this shift, showing that broadcast and the general live/installed audio markets are heading in similar directions.

At NAB RTS announced its first products for the OMNEO media networking system. Based on standard IP Ethernet and compatible with the emerging open AVB (audio video bridging) standard, OMNEO can be built into networks supporting from two to 10,000 linked devices, carrying synchronised multichannel sound operated using shared controllers. Media transport is provided by the Audinate Dante IP system, with OCA (Open Control Architecture) for control and monitoring.

RTS showed OMNEO interface cards for the ADAM matrix, allowing the intercom system to be used over “any standard IP-based network”. The company says OMNEO goes beyond AVB as it stands by combining OCA with both AVB and IP transports. Nico Lewis, senior sales manager for RTS Intercoms, comments that while other architectures can be used for jobs that call for support of “the entire range of professional applications, from the smallest to the largest”, offering full, reliable signal transport and remote control, only OMNEO has an integrated approach.

“We believe OMNEO is unique in offering a strategic, future-proof media networking solution that retains the ease of use that people have come to expect from Ethernet networks,” he says. “Other existing systems are based on Ethernet layer 2 and are confined to single sub-nets. OMNEO is fully layer 3 TCP/IP compliant and can span multiple sub-nets across wide areas. This reduces costs of materials and installation.”

But, Lewis says, the level of demand and choice of technology continues to depend on the user’s needs: “In live broadcast, the traditional RTS intercom is very popular because it is rock solid for critical communication. In these kinds of environment it is unacceptable that systems have audio delay and go down.”

Riedel is a long-term proponent of communications networking, mainly through its MediorNet system. At NAB it introduced the CPX-AVB expansion card for the Artist 1100 range of control panels to give full connectivity with AVB systems. Riedel also launched AVB Manager, claimed to be the world’s first AVB controller software, offering network management and system-wide control of all AVB devices.

“We believe AVB will establish as a standard in the broadcast and pro audio world,” comments Christian Diehl, product manager for intercom at Riedel. “The first network switch hardware will be printing AVnu certification logos on their products in the next months and the AVnu Alliance [which promotes and certificates AVB] expects to see enough pro audio products between the members to form an entire signal chain certified by the end of 2013.”

By using MediorNet and different interfaces Riedel has made it possible to carry intercom with the main audio and, in some broadcast situations, commentary feeds. This is still not universally accepted, due to the critical nature of each component, but Lewis says integration is “an important trend” in intercom: “The amount of possible integration is pivotal to the ergonomics of an intercom system. Standard AVB mechanisms like bandwidth reservation provide the necessary mechanisms to be able to reliably share the same infrastructure with other devices of a broadcast production and even the standard office IT networks, if so desired.”

Eric de Bruyn, managing director at ASL Intercom, sees further integration as a “good idea” but warns there should be a “separate intercom network” for security reasons. In terms of networking and transport formats, de Bruyn says Dante, AVB and Ravenna are the main contenders but that which will become the norm is still uncertain: “The industry has to make a choice but all these platforms are in the first place developed for one-way digital audio transport. Whether they are the best solution for the two-way audio of intercom remains to be seen.”

Trilogy Communications made in the first move into intercom using Voice over IP (VoIP) in 1999 with the Mercury system. This later developed into a distributed matrix intercom, Gemini, which remains Trilogy’s flagship product. The company launched Messenger, an intermediate product at CABSAT 2013, to bridge what it saw as the gap between Gemini and lower end two-wire party lines.

John Sparrow, Trilogy’s product sales manager, says many customers today are looking for a “flexible, user friendly system with comprehensive features at a good price”. Responding to this the company has introduced improvements to its Gateway configuration editor, allowing engineers to use advanced intercom functions more easily.

On the networking side Sparrow says more manufacturers have approached Trilogy to discuss compatibility with formats such as OCA, Dante, AVB and Ravenna. “The majority of these have analogue audio, AES, MADI and IP interfaces and Gemini is proven to interface to any of these standards, making the most of low latency networks such as Ravenna,” he comments.

According to Vinnie Macri, product marketing manager at Clear-Com, “Everybody is looking for low latency QoS [quality of service] connectivity.” He continues that each of the newer IP transport platforms offers some sort of timing features and prioritisation. “We’ve been selling IP solutions for a long time and the comms has always been easily implemented. Fearful issues like latency and timing have not interfered with our successful system implementations and interfacing. All of this to us is application driven. We’ve had meetings and have conducted exhausting research talks with networking hardware giants who see no long term plans to go in any of these directions. We broke our crystal ball a long time ago so we do not have an opinion on which approach might win favour with audio professionals.”

Delec Audio and Video Technology, on the other hand, has made an early commitment to AVB for Audio over IP (AoIP) using Dante. “It is the technology for the near future,” comments company founder Donald Dilocker. “Our Dante I/O boards can be seen as an intermediate until AVB is fully released. Our customers then only need to update the Dante boards to participate in the AVB standard.”

Dilocker sees both AVB and OCA as important for the future: “AVB opens up to integrated video transmission easily and the OCA Alliance offers a variety of new and product-overlapping control options.” Delec and the other companies of Salzbrenner Stagetec Mediagroup are founding members of the OCA Alliance. During Prolight+Sound the company hosted a reception to discuss the Alliance and recruit new members.

The general feeling about the intercom market is that it is in an intermediate state right now, with digital dominating but analogue still in there. Dilocker feels that while the demand for analogue is decreasing it will not disappear completely until the last systems in broadcast are replaced by those working on IP networks.

The big intercom companies currently straddle both digital/IP and analogue line systems of either two or four-wire. Some smaller suppliers are firmly in the latter camp, including Prospect Electronics, Anchor Audio, Sonifex and CTP Systems. CTP updated its Talkback24 system last year, partly in response to what founder Chris Thorpe describes as continuing strong sales for four-wire boxes. “And not an IP address in sight,” he says. “There’s no point in my trying to compete with Riedel, Clear-Com or any of the other big companies because they’re got lots of design engineers. But having said that the digitally controlled analogue Talkback24 has found a nice niche market among operators of smaller studios and OB trucks, where people just want to be able to plug in a jack and hear audio come out.”

Anchor Audio also takes the analogue route but with only two-channels for its wired systems. The PortaCom is a two-wire party line based on standard microphone cables supporting a full duplex two-channel network. “An advantage of this approach is that many studios, theatres and stadiums already have installed microphone cables which can be used to operate the PortaCom product without additional installation cost,” explains director of marketing Colton Jacobs, who adds that sales of the PortaCom increased by 17 percent from 2011 to 2012.

Jacobs says Anchor’s dealers are reporting a shift away from installed, base-station style intercoms to the stand-alone, portable systems. “That trend is happening because of the cost of the installed system as well as the professional staff required to operate the sophisticated equipment,” he explains. “Budget constraints in the broadcast market are causing the users to select low cost solutions.”

Modern technology still grabs the headlines and will push on how intercom systems are designed and used but financial expediency and basic user friendliness looks like keeping more basic techniques in the frame for some time to come.

Anchor Audio

ASL Intercom


CTP Systems




Trilogy Communications

Case study
The “super truck” is well established in outside broadcast work. These massive articulated monsters accommodate audio, video control and production control areas, bringing studio facilities to a location. A different approach has been taken by German OB operator Betamobil, which runs a fleet of small to large trucks that can be linked together to handle big productions when required.

The latest addition is HD6, a six-camera unit that also features a Riedel Artist digital matrix intercom connected to a MediorNet media network. The communications system features an Artist 64 mainframe with 12 1000 Series control panels, all of which can be expanded up to 1024×1024 non-blocking ports. All this can be integrated to other OB vehicles or broadcast facilities over a fibre link.

“We believe that the future of mobile productions lies within flexible set-up scenarios that can be adapted to the needed application,” says Thomas Busch, chief executive of Betamobil. “Riedel’s real-time networks, such as MediorNet and Artist, enable us to realise incredibly flexible set-ups that can be quickly reconfigured.”

Two MediorNet modular mainframes, fitted with MN-HDP-6 cards are used for video distribution and signal processing. The video cards provide two inputs and outputs, in addition to two assignable connections with full conversion features.

“With this truck we have realised a very efficient just-enough concept without sacrificing production quality at all,” comments Busch. “It’s just a very efficient set-up based on the MediorNet network approach. This allows us to adjust quickly to the needs of a specific production. By our approach we don’t have to always carry the expensive overhead for the few productions where we utilise 100 percent of a big truck’s capacity. If we need more cameras, editing, or audio resources, we just add it to the MediorNet network by adding another small truck or external gear. This flexibility allows us to cover more productions and to be more competitive.”

Intercom at the end of the 20th century
Back in 1999 the intercom market faced many challenges and problems that would be familiar today. Networking round studio centres, ever-growing OB sites, music venues and theatres was becoming a major consideration, with manufacturers and engineers looking at either replacing analogue with digital, combining the two or extending the capabilities of existing technologies.

Analogue two and four-wire systems were still firmly in the picture but there was realisation that the tide was turning in favour of digits. Just how much influence they would have was still not fully appreciated. One proposed approach to networking was interfacing ISDN, T1 telecom lines or even satellite with digital long lines.

Back then ISDN was the established broadcast inter-communications system and showed no sign of being replaced. A few months later in 1999 a new intercom system based on something called IP appeared. The intercom and pro audio world began to change from then on.