Know-how

Many people in professional audio see sound reinforcement as an inconvenient activity. It is obviously far easier to turn up in a familiar OB truck with everything perfectly prepared for a TV sound mix than to have to set up speakers and install a pile of gear! However, sound reinforcement can be a technically challenging and creatively exciting domain — which is demonstrated by this feature about professional sound reinforcement supporting a TV show recording

How do you approach sound reinforcement for a TV show to achieve the best result? A simple question, yet with many possible answers. The experts at SALZBRENNER STAGETEC MEDIAGROUP designed their own solution back in 2003. It all started when they were asked to support a Carnival show for the Bayerischer Rundfunk, BR broadcasting service. Planning the system is just the beginning. When the BR televised the Carnival show in the town hall of Memmingen, a small city in the German region of Swabia, the distributed system comprised 14 speakers installed right under the roof of the hall. Arranged as seven individually addressable loops these speakers reproduced a mix of all the various artists and the Carnival Committee’s radio microphones. This approach enabled the overall level to be kept low whilst optimising intelligibility thanks to the proximity of the loudspeakers to the audience. Another benefit of this distributed set-up became obvious whenever the actors left the stage and entered the hall. Whenever there was the risk of feedback, the level of the relevant loop could be reduced without adversely affecting intelligibility or the overall volume in the hall.
A second independent PA system was installed to amplify the band in the conventional manner. Thus, localization of the music was not disturbed, because at all times the instruments’ direct sound and the amplified signals were clearly emanating from the stage. Apart from the fidelity advantages, this dual system concept also provides a high degree of reliability.

In Groups
Seven reinforcement loops plus an FOH mix — the audio console must handle all this in a convenient manner. No problem for the AURUS, where operational convenience is a given! For this production, MEDIAGROUP’s two sound reinforcement audio engineers configured the portable AURUS console in such a way that it provided 16 group buses. The first use for these buses was to create submixes of instrument groups in the traditional fashion. For example, the brass section was combined into a group that could then be controlled by a single fader. These subgroups, plus the remaining spot microphones, were subsequently routed to the groups feeding the various speaker loops. Incidentally, the option of re-routing a group output to another group cannot be taken for granted on mixing consoles! However, with the extensively confi gurable AURUS, sub-grouping presents no difficulties whatsoever.

Which Bus to Take?
Obviously, master buses could have been used as outputs to the speaker loops instead of groups. With AURUS, the difference between these two bus types lies in the extent of processing available. A group offers full processing including filtering, EQ, dynamics and delay, while a master bus has no signal processing capabilities. On the other hand, the master bus requires less DSP power. Since the speaker signals required individual filtering and delay for time-alignment, the AURUS project created for this job utilised group buses instead of mix buses for this purpose.
On analogue desks, aux outs are often used for routing signals to separate speaker loops. The AURUS also supports this approach. However, group control strips are freely assignable on the control surface. This makes for better clarity and is far more convenient to operate.

Well Prepared
With shows of this order of magnitude, you have to take into account a longer rehearsal time. In this case, two days were allotted to install the system plus two rehearsal days. This was plenty of time to label all the band microphones properly, each of the 24 wireless microphones, and all other sources on the NEXUS/AURUS network. The individual names then appeared on the channel-strip displays and when setting up the routing on the NEXUS, thus signifi cantly simplifying operation during the rehearsals.
The engineers also programmed an individual snapshot for each scene of the show, a procedure that is also frequently used in theatres. Thanks to new editing possibilities for snapshots, this required minimal programming effort during the rehearsals while considerably simplifying the subsequent performance. At the end of the rehearsals, 20 such snapshots had been stored in the AURUS. This clearly illustrates why the AURUS, with a much more compact control surface compared with conventional desks, is more than adequate for such a task. Thus AURUS takes up less space during transport and in the hall while providing improved clarity. The sound-reinforcement team in Memmingen used a console with 32 faders that allowed them to mix the 60 or so signals quite comfortably using layers and snapshots. The topmost layer of the eight in each snapshot presented only the signals required at that moment. All other signals were hidden on lower layers. Each snapshot changed the assignments in the layers to show exactly what the scene required.

Live is Different
As is customary with German Carnival shows, the band plays short pieces and interludes time and again. Therefore the band microphones were statically assigned to surface faders, which never changed, thus allowing instant access. This simplified fast changes to the music mix. The stand up comedians and solo actors wireless microphones were however, handled in a completely different way. For each scene, only artistes performing currently were assigned to a fader on the top layer of the AURUS.
The prerequisite for this approach was the rather novel Isolate facility. As quite often happens during live performances, some of the musicians played much louder ‘on the night’ than during the rehearsals. These levels were manually lowered on the AURUS – but would have been subsequently overwritten by the now inappropriate rehearsal levels when loading the subsequent snapshot. Using the Isolate function, the signals in question were effectively removed from the snapshot, so the updated settings remained intact after loading a snapshot.

No Multicore
Sound reinforcement was just one of many technologies needed to produce the show. The lighting control desk, used to create spectacular effects, was situated next to the PA console. Crucially, thyristor buzz and interference simply weren’t an issue since the NEXUS audio network installed for sound reinforcement was based entirely on optical fibre, which is interference proof. A robust dual-core fibre cable connected the NEXUS stage box to another Base Device near the console. Conventional copper wiring was only used on stage and for the speaker lines.
It would even have been possible to do without traditional microphone splitters since the BR OB truck also uses NEXUS plus a CANTUS console. Thus, it would have been sufficient to run MADI lines from the NEXUS on the stage to the sound-reinforcement system or the OB truck. Another option would have been to use the split function of the new XMIC+ microphone input board. However, as these were not available at the time the engineers relied on the standard approach. The OB-truck crew set up their own dedicated on-stage NEXUS and used an external splitter to connect all the microphones to each of the systems.

In the Hall or on the Sofa
During the show, Memmingen Municipal Hall could only accommodate around 400 people. A much larger audience watched the show on TV. Taking this simple numerical difference into account, it becomes obvious that when recording a TV show, appropriate sound reinforcement must provide primarily for high-quality TV sound. Low levels, pure audio reproduction, and absolutely no PA feedback are the basic prerequisites of good TV sound. Which is precisely the reason for the extensive sound reinforcement at this event. This was a job for professionals — and a perfect application for AURUS and NEXUS.

The flexible AURUS bus routing enables even the most complex and unusual tasks to be handled with ease. AURUS fader strips are not limited to controlling inputs. In fact, when the console is configured, the group busses can also be assigned to fader strips and, just like a conventional input strip, can be allocated various processing options including filters, EQs, delay, and dynamics. Just as importantly the group outputs can be re-routed as inputs to other groups. For the production of the Memmingen Carnival tv show this feature was used extensively, abandoning use of the main mix buses other than for monitoring.