Know-how

With their big Ü2 O.B. Truck tpc international are acknowledged experts for complex location projects with excellent CANTUS sound. The live broadcast of the Knoff- Hoff TV-Show clearly demonstrated that the CANTUS potential extends way beyond broadcasting. It proved its prowess in both TV audio and sound reinforcement.

Know-How for Knoff-Hoff

TV audio and location sound reinforcement make uneasy bedfellows. Fading up the in-house PA to create a good liveatmosphere adversely affects the TV sound. If levels are reduced to create a clean and uncoloured sound for broadcasting then speech intelligibility for the live audience is compromised. In any case, without considerable expertise and close co-operation between the P.A. and TV-sound engineers, this classic audio challenge, so typical of TV shows with an audience, becomes an exercise in squaring the circle.

Slaves to the Hall

The Technical Approach

Our Ü2 Truck is equipped with a NEXUS audio network and a CANTUS broadcasting console. At production sites, the NEXUS network is normally extended to the spot where it’s needed — in this case to the stage and the control gallery — using portable base devices. This is very handy, as we do not need to lay multi-core cables. The NEXUS system only requires thin and flexible fibre-optic cables. In addition, the Truck carries a small CANTUS slave console capable of accessing the same resources as the main internal console. Both consoles share the available processing capacity. So, when starting a project where both consoles are involved, the total number of available channels is distributed between them. After this, it is possible to operate the two consoles in a largely independent manner.

For this production, the slave console was configured to access all sources connected to the NEXUS audio network. Thus, the NEXUS acted as a splitter because every microphone signal was available both in the O.B. Truck and at the FOH console. However, signals from replay devices such as MD or CD players, or video hard-disk players, were mixed in the Truck and were only then transferred, post fader via a direct output, to the slave console. This enabled the same fades to happen at both desks, which was important for the flow of the show.

The Knoff-Hoff-Show

The Knoff-Hoff-Show used to be a very popular show on German TV where the presenters demonstrated the basic rules of physics in a comprehensive “hands-on” manner. When the decision was made to revive the show, the producer awarded the commission for the audio production to tpc international.

Configured to fit

We were able to book Mario Obermeit, one of the sound-reinforcements experts of the SALZBRENNER STAGETEC MEDIAGROUP, to do the FOH mix. He was responsible not only for operating the CANTUS slave console, but also for setting up the entire P.A. system.

Since the actual sound-reinforcement requirements had only been roughly defined at the planning meeting, Mario Obermeit initially set up 14 separate PA areas. These areas allowed different signals to be routed to the various audience loudspeakers, the backstage speakers, the monitor wedges for the band miming to playback, the stage monitors, the producers desk, and so on. This large number of areas was reduced during rehearsals, once it became clear which areas could be fed with the same signals. The audio was routed to the individual areas using the aux paths of the CANTUS slave console. This demonstrated some of the advantages this console offers:

Firstly, it is possible to set up as many aux buses as necessary, which means it has the flexibility to adapt to virtually any requirement — assuming there is sufficient DSP power.

Another benefit is that the arrangement of the output paths can be very flexibly configured to exactly suit the specific task. For example, this might include notch filters, delay or compressors. The third advantage of the console is the clear overview of the 16 bus settings, provided by the central control module. The engineer can see at a glance the level at which each signal is sent to the bus. Finally, every signal path of the CANTUS can be freely labelled: “Aux 14” can be displayed as “band”, etc. This is a very convenient feature, especially with so many buses configured.

Digital Superiority

Time was an issue when completing the Knoff-Hoff-Show set-up, so the settings had to be made very quickly. Rehearsals started on the same day that the technical equipment was installed; wirelessmicrophone support and monitoring were required from the very beginning. Therefore, equalisation of the P.A. system and filtering of the wireless microphones was carried out at night, when the official rehearsals were over. Here, another advantage of the CANTUS became apparent: Wherever practical, channel settings were made and stored only once and could then be copied from one channel to one or many others.

Full Load

In total, there were almost 40 sources connected to the sound-reinforcement console. However, as this console is normally used for smaller jobs, it features only 24 faders. This is sufficient for the usual duties of a secondary O.B. Truck control surface.

Therefore, we used another CANTUS feature which enables up to ten different easily toggled control layers to be defined. Layer A contained all 22 wireless microphones, so it was almost fully assigned. All the aux-master sends were allocated to the faders of layer B, controlling the PA area levels. Layer C carried the signals coming from the O.B. Truck — the Knoff-Hoff band, video feeds, etc. — plus direct outputs from the live musician and the sound-effects man. This set-up resulted in a console that was still simple and fast to operate despite having relatively few faders.

Services during the Rehearsal

Reliability is always a concern when doing a live job. When recording a show with an audience, console failure could stop the entire production. This is also true for other CANTUS applications, for example, in theatres, or when doing live recording in the O.B. Truck or broadcasting costly performances of popular artists. Therefore, the console features a highly sophisticated reliability pack with a multitude of internal functionality checks, ranging from the constant monitoring of module boards and fibre-optic lines to the implementation of redundant power supplies. Moreover, as the mixing console is merely a remote control for the DSP rack, it can even be switched off during the performance without affecting the audio.

This functionality proved itself during the set-up. While searching for a cabling error during a rehearsal, we cut the power of the public-address console. The two presenters microphones and the aux buses to the FOH speakers were — and remained — enabled, so we could unhurriedly search for the problem.

A Multitude of Features

It was interesting for me as a long-time CANTUS user to see how quickly a soundreinforcement professional becomes acquainted with the console. Before this show, Mario Obermeit and his assistant Heiko Hannig had only been familiar with analogue desks. However, it wasn’t very long before Mario started talking to us about the optimum console configuration for the job, a notch filter here or a direct out there, and how he would have loved to do all the configuration work himself.

Next time — who knows? — we might be able to enable him to do this thanks to the NEXUS. We might integrate his laptop into the NEXUS network, so he could use the audio router to distribute and route to the PA areas himself and, for example, to enter delay times for the various areas. If the NEXUS is equipped with the appropriate DSP board, he could even use it for equalising the PA areas. This way, the slave console would merely be required for dynamic level settings and for equalising microphones.