Unless the broadcasting equipment is reliable, an undiluted and first-hand experience of the football World Cup cannot be guaranteed. For TV viewers worldwide, the sound from the match will be produced using audio mixing desks and crossbars by Lawo of Rastatt, Germany. Sound will be provided for South Africa via the four new outside broadcasting vehicles of the South African Broadcasting Corporation (SABC). All four OB vehicles are also fitted with Lawo equipment. One of the principal deciding factors in also choosing Lawo for sound control in the vehicles was the reliability of the mc²56 sound desks, which also feature an integral digital crossbar. The reliability of the mixing desk is further boosted by the use of Schroff systems.

Each of the thirty-tonne, identically specified trucks carries 18 cameras, including three Super Slow Motion HD cameras. Inside are four main areas: production, sound processing, recording and image processing. The sound processing area features a Lawo mc²56 mixing desk in a 32-16-16 frame that includes a fully programmable 64-fader user interface. This desk offers complete signal processing for each channel and 128 AES inputs and 128 AES outputs direct in its HD core. A Dallis I/O system provides additional AES and analogue I/Os. The router board contained in the HD core has a capacity of 8192 crosspoints. Other audio equipment includes three Glensound commentary stations, 5.1 surround monitoring, Dolby E encoding/decoding and a Pyramix audio workstation. Communications are provided via a Riedel Artist 144 x 144 talkback system with complete interfacing to the audio router.

Both the I/O systems and the Lawo digital crossbars and HD cores are based on 3 and 10 U europacPRO subracks from Schroff. Schroff also provides the backplane, power supply unit and fan units for these. The main requirements for the systems for the digital crossbars were: minimum possible dimensions, particularly of height; effective cooling design for the high packaging density, with a maximum dissipation loss of 600 W; EMC sealing; suitable power supply arrangements; and a backplane with 64 symmetrical line pairs with a data transmission rate of 1.2 Gb/s each. The result of a constructive collaboration is a system based on standard europacPRO components together with custom parts and solutions such as air deflectors, side panels with special perforations, rear component assemblies, reinforced backplane mounting, etc. An extra-low backplane and specially modified, compact, redundant PSUs were also developed to special order. The particular requirement for the PSUs was high capacity yet low space requirement.

A particular challenge for the 10 U system was to create optimal cooling for the electronics. The bottom area contains the two PSUs, which have separate fans. Above these is the area in which surrounding air is drawn in, passed through the 6 U high board space and drawn up, to the rear and out of the system by the fans. Because of the very compact design, certain measures were required to achieve the airflow necessary to avoid hotspots and the resultant detriment to the lifetime and functioning of the components. These airflow precautions, and the choice of the fans employed, also contribute significantly to the low noise level of this system.

Also in the Schroff systems for the I/O, the primary requirements are minimal dimensions and passive cooling. The biggest challenge here was the rear mounting of the two redundant power supply units in the system, which is only 3U high and with restricted depth. The solution is a folding mechanism in which the PSUs are mounted transversely and can be swapped even during system operation.

Another important element in the development of these systems was high reliability and availability. Maintenance can be performed on the digital crossbar while it is operating, and likewise it can be reconfigured or have elements removed during operation. Its hot-swap capability is therefore no longer limited to swapping components of the same type; now it is possible to expand the system during broadcasting operation. The pivotal point of every audio broadcast, the crossbars act as control devices for switching multiple signal sources between various output devices. All important components, up to the power supply system, have redundancy built in. The components in the Dallis I/O systems are also hot-swap capable, so that neither the failure or the replacement of an I/O board affects the remainder of the system. An additional redundant PSU and a redundant master board are also available as contingency reserves. The mixing desks themselves are also fitted with a redundant 400 W power supply unit.

It is to be hoped that the moments transmitted by this reliable broadcasting equipment will be mainly positive ones for the German team.