Deflected: Big Light Switch for Control Rooms and Studios
Five AURUS Control Rooms, Six Studios, and Ever-Changing NEXUS Combinations
Large all-encompassing single networks are history. Today’s approach blazes new trails, for example, the way in which campus-wide NEXUS and AURUS installations can be divided and subdivided into different sub-networks or islands. It is preferable that this should happen automatically, with full delegation of all parameters involved and, if possible, using a single fibre-optic switch. No, in an ideal world, not even by conventional switching, but purely optically by deflecting light through prisms. Exactly like the impressive Big Switch project in Zürich
In today’s broadcast world, the vision of a standard production landscape with HD video and 5.1 audio is not a revolutionary idea. However, the technical implementation at tv production center zürich ag (or tpc for short) experiments with new concepts and state-of-the-art technologies. No surprise — since tpc is well renowned for embracing the latest developments enthusiastically. With this change, tpcis also pursuing an entirely new goal, the technical harmonization of internal systems down to the smallest detail. The idea behind this has emerged slowly during the recent decades of handling digital technology. It is this: To make every TV production studio and every TV control room identical technologically so that any combination of studio and control room can be selected at the press of a button. This project is not only challenging in engineering terms but will be drawn out over quite a long period since it requires considerable alterations to the existing infrastructure. The upgrade process is divided into three stages and is scheduled to end in 2012; the first stage has just been completed.
Despite the increase in flexibility, which allows almost any control room to interconnect with almost any studio, audio set-up and configuration effort must be minimized. This means that all signal routers, controls, and logic switches involved should be re-assigned automatically when a making a change. This can only work if the interfaces between studio and control room have been standardised and specified down to the smallest detail. Identical console configurations must also be available in each control room, created specifically for each type of broadcast. If it is known which fibre — tpc consistently uses optical fibres, often in combination with CWDM (Coarse Wave Division Multiplexing), for interconnecting various rooms — transfers which signal, for example, from a studio to a control room, that fibre can in theory be patched to a different control room with exactly the same set-up. The systems involved will not be affected by the changeover, and the user can start working immediately without having to worry about basic infrastructure settings first.
At this point, tpc goes one step further. Instead of patching a control room to a studio manually, changeover is now accomplished by a passive optical switch. The decision was made in favour of a Polatis optical change-over switch which uses switchable prisms and is able to route 16 incoming dark-fibre lines to 16 outgoing lines. This device operates with impressive mechanical precision because the internal routing of incoming line to outgoing utilizes prisms, which must be tilted appropriately to deflect the optical signals as desired. Since this optical router simply deflects the light instead of interpreting the received signal, it is completely transparent to the connected systems. Therefore it is irrelevant whether the routed optical signal is a NEXUS network link, a MADI line, or even a video connection. Compared with the STAGETEC OMUX, which converts optical signals to an electrical format, routes them, and reconverts them back to optical signals, the optical router offers increased flexibility to tpc, in particular, with regard to future developments. As a reference to the fact that the system is indeed capable of switching all the relevant audio and control signals, the optical switch acquired the in-house nickname »Big Switch«.
The Devil is in the Detail
The principle difficulty with the project is, however, not in switching the optical lines, but in specifying and fine-tuning the configuration. Since all signals involved in audio in the broadest sense are carried over optical fibres and the Big Switch, they need to be harmonized for all participating control rooms, studio patchbays, OB vehicles, and mobile NEXUS units. For this reason it is necessary to define for example, which intercom wireless signal enters the system on which Base Device and port and where and on which port it is output again and sent to the wireless link. The same is true for the XRI boards’ configuration, the logic programming, the red-light signalling, the standard intercom, and so on. All these elements need to be configured identically in the studios involved so that change-overs and delegation will work.
Yet another extension has been planned. In addition to the fixed control rooms within the building, at peak times, an OB truck will serve as an additional external control room for studio productions. This is because, when the extensive upgrade is complete, tpc will have six studios but only four control rooms, so the option of using an OB vehicle as a fifth control facility is a welcome addition.
Obviously, this also means that all OB trucks need to be adapted to the Big Switch concept with its consistent Base-Device enumeration and configuration — again, down to the smallest detail of red-light signalling, logic programming, etc. The two existing HD-enabled OB vans have already been modified accordingly. And for the new additions to the fleet, a configuration matching the Big Switch concept will be implemented right from the start.
Base Device 11 again and again
In detail, the in-house harmonization looks like this: Each studio has a large 3-level Base Device which is always run as Base Device Number 11 and with exactly the same logical configuration in each studio. It serves as the switching centre since its NEXUS boards receive and forward all audio-related signals between control room and studio. Now, when a control room is connected to any studio, the NEXUS network in that control room expects Base Device no. 11, which is used as a quasi extension to the studio, to be present. In this way, the NEXUS in the control room does not even »notice« that a changeover has occurred — the studios are, after all, identical in terms of logical configuration.
Since it would be overkill to actually equip each studio with a fully populated Base Device, only the Base Device in Studio 1 is equipped with the full complement of boards. The other studios Base Devices house only the essential boards although they are ready to be populated fully. In practice, this means that additional boards can be installed into the Base Device as required without having to reinstall a new configuration afterwards. As a long-term NEXUS user, tpc has a large pool of boards and can utilise this resource even more efficiently thanks to this trick.
In addition to Base Device 11, up to four mobile Base Devices can be connected to a control room. These are used, for example, as stage boxes receiving the microphone signals from a band in the studio or for extending the number of possible input channels. For years, tpc has relied on a pool of portable Base Devices for OB vans. All of these are also configured identically and have a notable feature; a small rotary switch. This is used to set the Base Unit’s logical number manually to a value between 15 and 18. This philosophy has been transferred to the studios and control rooms so that any of tpc’s mobile Base Devices can be connected to any control room or OB truck.
Yet More Flexibility
However, total harmonization requires more than just creating uniform NEXUS networks. The mixing consoles must also be compatible. In short, the entire control-room configuration must be standardised. Only in this way is it possible to allow for changing control rooms, right in the middle of a production, without manual intervention. This was one of the essential requirements: To create an ideal scenario for optimal room allocation and to deal with possible failure situations. In order to achieve this, all AURUS projects are not only stored locally on the respective consoles, but also on a central server. When a production is moved to a different control room, the relevant project can be downloaded from the server to the AURUS in the new control room, thus moving all project settings as well. Using the »Save NEXUS« function, implemented in the AURUS software, it is also possible to store a snapshot of the current NEXUS routing configuration.
Once the technical changes and harmonization have been completed, daily operation will become much easier for the audio crew. The optical switch does not even require manual operation — the unit has been integrated into the global control system of the entire production complex, the BFE KSC-Manager.
At the start of a shift, the operator in the audio control room first selects a studio he or she would like to link to. To do this, the operator only has to press two keys on the KSC-Manager control unit — for example, the Studio 1 key and the Trigger key to initiate establishment of the interconnection. Then the KSC-Manager controls the Polatis router in such a way that all the optical lines involved — audio, Tally, intercom, and any other signals required in an audio control room — are connected. The control unit also ensures that a connection between the control room and the studio remains locked once it is established. The connection cannot be broken by another control room until it is released from the original via the KSC-Manager.
Big Switch in Use
Control Room 2, an old control room equipped with a NEXUS system from the Matrix 4 generation, a CANTUS mixing console, and SD video systems, is due to be upgraded to an AURUS and HD late in 2010. When this upgrade is complete regular operation of the Big Switch will start on a small scale with two studios and two control rooms. The Big Switch has already been installed and all the details will be checked thoroughly until the end of the year.
Before the Big Switch enters general service tpc will celebrate another premiere: On the 20th of March 2010, the first production from the newly completed Control Room 3 will occur. This will be an edition of one of the biggest live shows on Swiss TV. A line-up featuring international singers, comedians, musicians and vaudeville acts, presented by Beni Thurnheer, one of Switzerland’s most popular TV presenters, and combined with a million-franc lottery. How could the Big Switch possibly make its debut at a smaller event? And even the name of the show is apt: It is called simply Benissimo (Fine).
The Project Stages
The overall concept of this project involves all audio and video production suites at both the main complex in Zürich and all the tpc OB vehicles. This is a substantial challenge because not only does it involve replacing all SD-video components with HD systems, but also because an extensive upgrade of the entire digital audio-production infrastructure is required. tpc were among the early adopters of digital audio and optical networking, and a large proportion of the components (some of which are almost 15 years old) had to be adapted to the increased requirements, modernized, or replaced during the course of the project. A key element is the transition of the audio system from NEXUS routers of the outdated Matrix 4 generation to the current Matrix 5 version and together with this, replacement of the old CANTUS consoles with modern, large, AURUS consoles. Due to its extensive scope, the Big Switch project had to be carried out in several stages. In the beginning, before the modernization was started, tpc had six control rooms and seven studios. Some were then re-purposed and will finally be rationalized into four modernized control rooms, six studios and a facility for interfacing an HD-enabled OB truck to be used as an additional production control room.