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An Audio Board - TvTechnology

An Audio Board

Digital technology adds to the complexity of buying an audio board. While digital boards are very reliable, they are still subject to failure over time. Making sure that a digital board under consideration can easily do the tasks you need it to do today and tomorrow is just part of the evaluation process.
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Buying an audio board used to be a pretty straightforward process once you’d answered some basic questions:
-How does it sound?
-How big are the productions it will do and how many channels do we need?
-Does it work the way we’re used to working so we don’t have a learning curve?
-How much space do we have?
-How easy is it for us to fix?
-Does it have enough EQ, compression and outputs?

Oh, and of course there was price. With analog, there is a visible correlation between features, quality and cost. Analog technology is pretty well understood, so as long as it has enough features and is familiar enough, it’s fixable!

We don’t need quality we can’t afford!

However, once you make the decision to go digital the same questions apply, but in addition there are other issues to be considered that you’ve never had to think of before.

In a broadcast environment, staying on air is more important than any other issue. This becomes more critical with digital boards as digital boards provide more functions per circuit card than analog. If you a lose circuit card in an analog board it probably won’t have a catastrophic effect on your ability to complete the job. On a digital board the opposite applies—the loss of one circuit board could mean the loss of a significant number of channels and other facilities, or worse, no outputs at all.

A well designed digital board is very reliable, but digital components are no different than analog ones. They can always fail over time and anyone who believes this isn’t so has a level of blind faith in technology (or sales material) that defies human experience to date!

Redundancy

To overcome the potential for hardware failure, it is crucial to ensure the design is comprehensively resilient. The design should distribute facilities across the system so that failure of one card does not remove all your outputs or take away all your control. Key elements such as DSP and control system circuits need to have automatic redundancy to cope with the potential for failure over the life of the board. You won’t be able to repair circuit cards and you don’t want to have to power down to replace them.

When buying a board, you really need to fully understand how redundancy is provided and how it copes with staying on air if you need to remove something. Everything needs to be capable of removal and insertion/re-set under power. It is surprising how many boards are still unable to provide all of this, and there is no better way of ensuring it can cope than asking for an unrehearsed demonstration of redundancy and hot-swapping. You owe it to yourself to insist on this. And while you’re at it, turn off the power at random and see how well and how quickly the board gets back to where it was. If you have power outages or brown-outs, digital is a lot more unforgiving than analog!

As far as software reliability and reliable booting-up goes, there is no easy way of ensuring that the system is reliable other than asking the supplier for a full customer list and calling some of them up... try it for yourself, it can be a real eye-opener.

The Joys of Digital

The next decision is how easy it is to use and how well it helps you make use of the increased facilities digital architecture offers. Most digital consoles can provide enough channels for what you need, and as long as you’re not going to increase the size of your production dramatically, you need to make sure that’s enough for now and your move into 5.1.

Signal processing is also much better provided for digitally, as EQ, dynamics and delay are usually available on all channels, often removing the need for outboard processing. However, with digital boards there are usually more channels available to the operator than faders provided. That sounds great—and it is—and with the onset of more 5.1 sources, it’s absolutely necessary. But with the provision of more channels you need to consider how the manufacturer provides access to them and controls them.
This usually employs some means of “layering” of channels, allowing them to be hidden beneath the faders. Making layering work easily and intuitively in a live situation is a crucial requirement. There should be as few steps as possible to get control of channels; having them buried on hidden layers or banks can be a real problem when you need to use elements that are hidden three or more layers deep.

At Calrec, we make only live broadcast production consoles, so we took this issue very seriously when we decided that some layering would be required in the digital future. On our boards there are two signal paths available to each fader and access to either is a single button press. All your live channels are in front of you and visible at all times, nothing is buried.

This is worth checking, as it’s not just faders that can be buried. Other controls can require paging or interrogation such as your groups, program outs or pan controls.
Moving from an analog board to a digital one can, not surprisingly, make people very nervous and being human (that’s right Mr. Station Manager, even audio engineers are human) we all look for the safety of the familiar. For many people, that translates into “I want lots of knobs for each fader.”

At Calrec, we came across this over 20 years ago when we introduced the world’s first digitally controlled assignable board for broadcasting. After a long period of talking to operators, we saw real advantages to having as many controls as possible immediately in front of the operator instead of spread across the width and height of the board. We also provided some local assignable controls for setting up things like IFBs and mic gains.

Now, nearly every digital audio board available includes some assignability. But assignability means different things to different folks. The key thing is how easy the assignable facilities are to access and use. That’s what tells you how many local controls you’re really likely to need.
Generally, no more than a few local controls are really actually needed. The thing to do is sit at the board and look at the access in terms of what you really need to do, day in, day out and see how much effort is required to do it. Well-designed assignability will make life easier and less stressful.

While we’re talking about facilities, an assumption often made of current digital boards is that, like analog, they have all their facilities available at all times. But this is not always true and it is vital to check that the board does not “pool” resources. Make sure the buss structure provides everything you need all the time. Some boards can offer a pool of busses that can be used for different things, but not simultaneously. Some can also lose DSP functions (EQ, dynamics, etc.) as busses are used. That may be OK today, but it is unlikely to be so as 5.1 operations become the norm.

The Digital Golden Rules

Generally, if you are looking at digital boards for the first time, it would pay to adhere to several golden rules:
-Do not assume that all digital boards are alike. They are not, and they do not all address the above issues successfully.
-Don’t be impressed with the first one you see. All modern digital consoles offer more flexibility and processing than analog, and they all offer glitzy stuff such as TFT metering and memory recall. Ask the fundamental questions about resilience and check how easily they do what you need them to do. You will quickly separate the real players from the rest.
-Make sure the board you buy has a development future that can cope with your growth and changing needs. We live in a world of constantly changing production demands. Ask whether networking is available and whether it has the capacity for growth. Networking can save significant costs on installation, especially if you have or may have multiple rooms and studio floors. It enables your future development to be cheaper and more flexible, and so is a very real consideration.
-Lastly, always get a user list and contact your own choice of existing users and ask them about their experience of the product and support... anyone with a good product should have no problem with that.

John Gluck is sales and marketing director at Calrec Audio.

He can be reached at john.gluck@calrec.com.