Audio in byte sized chunks

Digital audio development is well into its second decade, and there are a lot of products available to the integrator. But does this actually equate to freedom of choice when it comes to system design?

“For the last ten years,” begins Digigram’s Jimmy Kawalek, “we’ve basically been trying to replicate digitally what we could do in analogue. And now, at the end of this first decade we’re finally getting to the point where we’re starting to implement things digitally. By which I mean we’re looking at a product from the digital domain, not from the analogue domain. There are now multiple manufacturers out there who are bringing out truly digital products, which were designed to be so from the ground up.”

What Jimmy is driving at is that instead of simply looking to do things digitally just because its possible, manufacturers are really starting to come up with audio products that truly harness the full potential of digital technologies. Almost every major audio manufacturer now has a “digital” product offering of some sort and choosing the right one can be a minefield for the unwary or under informed.

For commercial installation purposes the key products are the DSP (digital signal processing) and audio Matrix products. But even amongst these there is a huge variation in cost, scale and features.

The feature sets range from the very simplest digital sound processing functions such as EQ, and delays with limited I/O counts to fully scalable systems capable of handing hundreds of channels of digital audio for massive projects such as sports stadiums or airports.

Amongst the simpler systems around at the moment is Allen & Heath’s iDR range. The company’s Product Manager for iDR is Leon Philips. “iDR is a DSP matrix mixer with extensive management and control options. We pride ourselves in offering a lot of onboard tools for management of the various jobs, and ways of controlling it. It’s not just a dumb black box, it really has got ways of integrating with your system.”
The range contains two key products, iDR8 and iDR 4. With 8 and 4 XLR inputs / outputs respectively. There are also various remote control options, including wall plates, IR hand sets as well as the increasingly important ability to connect to the device via Ethernet and control it via a PC or laptop. Expansion devices are also available to increase I/O count.
Another important feature are the 256 possible preset configurations. Everything from the functions of the softkeys on the remote to the display provided by LEDs and LCD on the front of the main unit to the DSP settings themselves can be assigned to a preset. These can be switched between at will, and thanks to the iDR’s real time clock they can also be scheduled to change automatically.
Allen & Heath set out to product a truly flexible product and Philips cites applications ranging from a mixer / zone controller in a restaurant to a microphone mixer in a conference for an events rental company.

Another product competing for the midrange market is Biamp’s Nexia. Unlike iDR, which comes in one configurable flavour, Nexia is available in a number of different application specific variants. Ian Hodgkinson, European regional sales manager, explained: “Nexia comes in a few different configurations to make it easier for people to work out exactly what model they need for the project they are working on. And it also comes with default programmes built inside it. Nexia you take out of the box, plug it in, and it works. It’s a simple DSP for people or projects that simply don’t justify the extra time required programming a more complex solution.”
Variations on Nexia include the CS (conference system), VC (video conference) and SP (speaker processor) which all come pre-programmed to perform the stated task. If more inputs or outputs are required it’s a simple matter to stack together two or more of the same unit.

In the case of Biamp, a more complex solution could mean using AudiaFlex. This is a modular system, where the user decides how many inputs and outputs are required, and then buys a DSP mainframe and the various I/O cards that are necessary for the application in question. “With these two products, “ concludes Hodgkinson, “there are very few applications that we can’t offer a solution for.”

The Harman Group’s offering in the DSP / Matrix space comes in the shape of the well established Soundweb London from BSS Audio. London first appeared in 2004 designed to be easy to install, design and control. The core product is BLU-80 a digitally networkable DSP processor and matrix which can accommodate a total of 16 inputs or outputs in any combination of pairs. It also comes equipped with a dual redundant CobraNet connectivity module. A second unit, the BLU-32 can be configured just like the BLU-80 but acts only as a network break-in / break-out unit with no DSP. This saves costs in jobs with a high I/O requirement but no need for lots of DSP.
For smaller systems where a network is not required, the BLU-16 has a identical I/O and DSP capabilities to the BLU-80 but no CobraNet card. BLU-10, BLU-6 and BLU-3 are a series of remote network controllers ranging from a programmable touch screen to simple switches and faders. The numerous serial port and GPI connectivity options mean that London can also be controlled via systems such as Crestron or AMX.

At the other end of the scale from Soundweb is the ZonePRO line from dbx Professional. Like Allen & Heath’s iDR, the inputs and outputs are entirely analogue, although the connectors are Euroblock or RCA rather than XLRs and the box contains a strong package of DSP functionality. ZonePRO is available in four models, the 641 and 641 as well as the 1260 and 1261. The 640 and 641 feature four zone outputs and the 1260/1261 6 outputs. They are both controllable remotely via an IP connection as well as from the front panels.

NetMax from Electro-Voice is another possibility, although aimed more at the live sound market place. It combines both analogue and digital audio routing, mixing and matrixing; CobraNet audio networking, digital signal processing and a variety of options for data connection and control, TCP/IP networking, remote control and supervision.

QSC offers an end to end digital audio solution under the overall heading of, based around Microsoft’s .net software technologies. The DSP hardware platform, Basis, includes some eleven models with various I/O configurations. The majority of them also being fitted with CobraNet cards. QSC make much of the fact that you can use a whole system made from their product from microphone to loudspeaker, however you can just opt to use Basis as your DSP engine.

Arguably at the top of the features and power tree for the moment is MediaMatrix from Peavey Electronics. The latest incarnation of MediaMatrix is the NION system. Dave Bearman operations director commented: “MediaMatrix is basically a scalable hardware and software combination of DSP audio processing and control and transport in an integrated package. We predominantly we use CobraNet, although we have just signed a licensing agreement with EtherSound.

“Although to get the most out of CobraNet and its advanced routing capabilities you have to integrate control of that into the product. And that’s fundamentally where MediaMatrix differs from a lot of the other products. The control capabilities that you get with it allow you to do some of the more clever stuff that CobraNet allows you to do. Most of the competitive DSP audio processes are exactly that. They have a GUI that allows you to programme them and control them, but MediaMatrix has a much more capable control layer. If you look at particularly large systems, which integrate with other parts of the building – fire alarm, management systems or whatever, they have to have some form of interface to allow them to talk to those systems. MediaMatrix allows you to do some very clever control things with those other systems thanks to its high level scripting language. It’s a more complete product.”

When talking about digital audio, the digital processing is only half the fact. The second step is transporting the audio data digitally. Some of the products mentioned above simply have XLR input’s and outputs with DSP in the middle. Others allow the user to make use of one of the various transport methods via option cards or a choice of I/O.

Until recently, the only real options for digital audio transport have been the competing EtherSound and CobraNet standards. Much has been written about the relative benefits of either protocol, however many in the Pro Audio industry state that the competition between the two is in fact harmful. In an ideal world, the differentiation between digital audio products would be about feature set, audio quality and service to the client. However the situation as it exists at the moment means that people are forced into one camp or another.

This situation at the moment shows no real signs of abating. Indeed more different audio transport protocols have sprung up in recent years. Roland System’s Digital Snake takes a slightly different approach to the “big two”. The main difference being channel count. As opposed to the 64 offered by EtherSound or Cobranet, RSS opted to reduce the channel count and up their sample rate. Digital Snake therefore carries 40 channels of audio over standard Cat5 cables sampled at 96kHz / 24bit. This makes it a great solution when a user doesn’t need so many channels, and audio quality is more important.

Right at the other end of the channel count is OptoCore. Andreas Kaspar, product manager explained: “Optocore is a fibre optice transport system capable of transporting different signal types in one fibre with low latency, a high number of channels and over a long distance, all at the same time.
“The current specification is for 256 audio channels, 3 video channels, 32 dmx channels and 100mbit fast Ethernet.”

Fibre optics offer several advantages over traditional cables. There is no interference or electrical hum. However, they are generally thought of as being more expensive. Kaspar responded, “If you look at the cost of carrying 200 audio channels on rival products then we are highly competitive. It’s therefore a choice of how much capacity you need. If you only need 40 channels then you don’t need Optocore, but if you look at a stadium or an airport, when you need that number of channels and redundancy, there’s no way around Optocore.”

Digital audio has a great deal to offer integrators and their customers. In the words of Jimmy Kawalek, ”Cost savings come from the removal of infrastructure, and from having more upgradability, flexibility and greater control of your system.”

However at the moment there’s a worry those benefits come at the cost of fully open systems, and ultimately a lack of freedom of choice of technologies.

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