Whether it's for a newly constructed broadcast or video production facility or an upgrade to an existing studio, selecting a studio production audio mixer is a significant investment, and once the installation is done, there's no going back.
The basic key to selecting the right audio board for the job is, quite simply, to know exactly what that job is. And there are as many different scenarios as there are control rooms in the broadcast industry. However, following some basic tenets greatly enhances your chances for ongoing success.
Of course, the widest selection is possible during initial construction planning. In an existing room, it comes down to whether you're willing to knock out a few things and do some woodwork. If no modifications are possible, the choices fall only within the outside dimensions of the mixer surface and the rack space necessary to house any support hardware. It is in this last situation where production operators typically clash with the contract installers trying to save cable and other hardware costs while the operators are concerned about what can be reached and from where.
Add to this the fact that in many control rooms, the audio board is frequently doing double duty, first recording a show and then requiring a reconfiguration for posting that show or another production right away. Live and post are two different environments. (See Figures 1 and 2.) In post production, things can be done carefully so they're just right, like a surgical procedure in a big hospital. But in live TV sound, the technique is more like that of a field MASH unit. Hit the music; hit the mics; roll the credits; and bang, we're out.
There are some great features on the digital mixers, such as using digitally controlled amplifiers to turn the input faders into an equalizer and switching their control from inputs to outputs. But if you're only doing live and live-to-tape production, chances are these expensive features won't be needed.
The past and the future
Analog mixers have a long history in TV control rooms, and they will still be found there for a good while, but the comparative price issue between analog and digital mixers melted away a decade ago when the small digital project boards hit full market speed. But now, even with many more tools available, the bedrock issue is still a thorough understanding of what specific things the mixer is going to do. Beyond this, how it can be augmented with hardware and software to accomplish future missions is important. Digital boards maintain two huge advantages in this regard. They can be totally reconfigured in seconds, and software upgrades can add substantially to capabilities over time. The three primary fields of consideration are: control surface, signal processing and input/output capability.
Some questions to ask when looking at digital boards: In the event of a power glitch, how fast does a digital board reboot? Can a dual-redundant power supply take over without any interruption in the program sound? If one fader bay should fail, how quickly can the control surface be reconfigured around that problem? The reconfiguration should, at the same time, reroute inputs and outputs while setting all channel strip processing to duplicate that on the previously used strips.
Another feature that is frequently overlooked until the moment it's needed is the cue buttons function. Are these latching or momentary contact only? Momentary contact and after fader level is typically appropriate for mixing live music to isolate the instruments while dimming the program mix.
But for live multicity interconnects with guests participating from remote studios, a latching prefader cue function can help when the host would like to talk briefly with remote guests before the program, while at the same time, the master control engineers want tone and bars on the line for the uplink. Mute busses can be useful for this, and prefade auxiliary outputs are also handy if they can be controlled in unison so that selected mics are sent to mix-minus feeds and IFB inputs without going online. Then, with one button push, the IFB feeds are all switched to follow the line mix for the show. On analog boards, VCA faders are made to order for this so that multiple mics and line sound sources can be centrally mixed on subs without on-camera guests hearing rewinding tapes or distracting conversations in their IFB earpieces.
Input routing control on the mixer is a feature that expands its usefulness substantially, particularly if it can use a standard protocol to work in concert with the station video router. If live music is a frequent job, the quality and type of mic preamps is of prime importance along with the length and smoothness of the faders. At least 100mm fader length is needed for live music mixing.
Prefader metering on each input channel strip can also be useful in a TV studio production board for quick visual confirmation of signal presence on individual channels without any button pushes. General-purpose interfaces for machine control can also help in allowing the operator's hands to stay on the board most of the time instead of poking around racks, a useful thing in mixing a live news open with a music bed or montage playing under a series of in and out remote mics.
When the local studio is being used as a source into a live show anchored elsewhere, there may be a need to program the monitor feed to the producer, director and TD in their room to carry the local host mic continuously in one speaker with the mix minus feed from the anchor station in the other control room speaker. A digital board can be easily set up for this through a prefade auxiliary output or direct channel out. It's important to maintain the flexibility in video control room monitoring either through electronic or manual patching for this type of monitoring configuration.
Live studio audiences introduce a whole new equation to the setup. Depending on the show format, the mics can be split in the studio with a separate PA operator, or direct outs that might normally be used for feeding stage monitor mixers can be fed back to the PA board in the studio. However, of course, any change to the control room board's attenuator pads could affect both. For simpler formats, a post-fader aux mix can feed a power amp in the studio but this requires a careful level check prior to show time. When this is the method used, plenty of switchable prepost aux outputs will be a must for the control room mixer.
With the coming of digital audio network technologies carrying multiple channels of uncompressed, bi-directional pulse code modulation sound on twisted pair cable, a mixing console with slots for Ethernet modules is a must. The latest development on these has slide-in modules that are multiprotocol.
The idea of using a digital board with such advanced capabilities may be a little scary for a production manager realizing that at times when the A-team is off, there might be simpler productions with less experienced people manning the control room gear. But that's the best reason for having recallable setups. This way, if the junior league operators get into trouble, they only need to hit one magic button to get the board back to where it was.
This is particularly good for the EQ settings, which is where a lot of inexperienced audio operators get themselves into trouble. Yes, EQ knobs do turn to the left. I/O should be modular and expandable without requiring the purchase of loads of extra boxes to mix and match digital and analog outboard gear. Integrated routing is fundamental, and there should be support for digital formats, including SDIF, TDIF and AES/EBU.
A removable recording medium is also a basic factor to be considered, especially if this mixer will be one of a group of the same make and model. The ability to move the setup parameters to another control room is a tremendous time-saving asset.
If the board is also going to be used for post production, automation features must be included, and most digital boards can be reconfigured quickly for this, including the integrated rerouting necessary. The routing is somewhat different for TV control rooms because your mixer may be chasing remote machines that are being used for video posting at the same time. In this situation, monitoring and automation features must work together in the saved setup.
Careful consideration of the mission and whether every conceivable production and post-production scenario falls within the configurability of the mixer is the key to making it work.
Bennett Liles is a writer and TV production engineer in the Atlanta area.
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