Monitoring the audio monitors11 April 2012
The basic functions of audio monitors have not changed substantially in the last 50 or so years but the scope of what they have to do has increased considerably, as has their overall importance in identifying and verifying differing signal types. Digital control and transmission has made a great difference to this field but now monitoring equipment manufacturers – and the personnel who use the gear – are facing another step forward as broadcasters gear up for full file-based delivery.
Preparations for the eventual implementation of tapeless, data operations in broadcasting have been made over the last ten to 15 years. Among the first open standards developed for interchanging audio-visual material, plus associated metadata was MXF (Material eXchange Format). This has been followed by AS-11, an international format for delivering completed programmes from production companies and distributors to the broadcasters developed by the Advanced Media Workflow Association (AMWA).
For audio AS-11 specifies either PCM stereo, AC-3 (Dolby Digital 5.1 surround sound) or Dolby E. Two EBU recommendations are also used as templates for audio production chains: R48, covering allocation of tracks in basic stereo; and R123 for exchanging audio with multiple channels, including up to three different language channels, plus one or more sets of 5.1 or stereo.
These new configurations will make even greater demands on audio monitors, which are already having to cope with discrete multiple audio channels as broadcasters move away from compressed carriers like Dolby E. Terry Allford, who was head of production services at BSkyB before joining Wohler Technologies as business development and channel manager for Europe, the Middle East and Africa, says that while 2 or 4 pair monitors are still adequate for small facilities, big production centres need "at least" 16-channels.
"This means they can deal with a 5.1 mix, stereo and any analogue channels, monitoring them all on a single panel," he says. "This will include a minimum of two Dolby streams and two separate languages, also in Dolby. In many situations people also need to decode signals as well as monitor them."
Wohler is addressing this market with the new the AMP1-16M dual input 16-channel SDI monitor (pictured), a 1RU rack-mount unit that handles embedded audio in combined 3Gb/s and HD streams or SD-SDI feeds. Along with Glensound Electronics and BCD Audio, Wohler has supplied monitors for Sky’s new Harlequin 1 (H1) broadcast centre, now re-named Sky Studios. More than 100 Glensound GS-MM83 units have been installed at Sky Studios and were customised on site. "We visited Sky with our design system on a laptop and tuned two separate positions so the unit could have preset dynamics for voice, music and flat," Marc Wilson, Glensound’s sales and marketing manager, explains.
UK manufacturer and systems integrator TSL installs monitoring units as well as making them. Its products include the PAM2-3G16 and the new AVM-T-MIX, which was originally designed for the BBC Sport facilities at MediaCityUK, where it is used by production staff, including directors, PAs and editors. TSL audio applications manager Martin Dyster says monitors continue to play an important role in the infrastructure functions "on the edges" of main production, including ingest, lines management and master control rooms. He adds that a recent trend now influencing the design and choice of equipment is new broadcast centres being built as either 3G or 3G-ready from scratch.
Although modern digital equipment, such as large mixing consoles, now incorporates more functions, including audio routing, Barry Revels, who manages UK sales for BEL Digital Audio, observes that dedicated monitors are still necessary to detect faults. "Systems are getting more complicated with multiple channels," he says, "so operators can’t just look at the console and see if there is a problem. Things might have gone wrong before the signals get to the desk."
Revels is seeing growing demand for audio monitors on major projects, such as the Olympics, the 2010 Rugby World Cup and this year’s Australian Open tennis championship, where Gearhouse Broadcast used 52 BM-A1 monitors.
They are often hidden away in racks rooms or equipment cabins on location but audio monitors continue to play a crucial role in getting the right signal in the right format to the right place. Which means they will continue develop and won’t be going away anytime soon.