Differing approaches to providing audio solutions are emerging in the broadcast world. Audio over IP is a given, but where to start and which vendors to choose are proving tough decisions to make, especially as the hardware investment can have a ten-year life expectancy. And moving from an analogue, MADI or AES system can be a daunting task for any broadcaster.
Integration, connectivity and interoperability further muddy the waters as chief engineers decode vendor solutions. And automation is key to any new installation as businesses fight to simplify workflows and remove human intervention, not just to save costs, but equally to remove human errors.
When moving to an Audio over IP infrastructure, the first difference engineers will notice is the audio console is physically smaller than even their digital audio counterparts, and doubly so if they’re moving from analogue audio. In the decentralized IP world, the sound console does not necessarily process audio, instead it will have an IP connection to one or more processing engines. Truly distributed systems allow for the processing to be done in another room, building or even state.
Modern, decentralized audio consoles do not have to bother with processing copious amounts of audio data, their power supplies are physically smaller, and the amount of heat generated is significantly reduced, all resulting in a quieter operation as there are no fans needed to keep clock hungry silicon cool. As there is less heat being generated, smaller studio air conditioning units are required, allowing the sound engineer to focus on their mix without interruption or distraction.
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Routing audio is altogether different too, gone are the FET x-y matrices and patch panels. Instead we have an array of network IP routers used in the IT world, and this is where it starts to get complicated. Engineers must move their thinking from point-to-point connectivity of audio source and destination endpoints, to meshes of network resource. In addition, IT network connectivity is bi-directional allowing us to send audio in both directions over a single cable.
However, IP routing provides other challenges. Source and destinations audio patch bays are replaced with IP addresses, a thirty-two-bit addressing scheme that defines the source and destination of every IP packet. Address masks, gateways and MAC addresses add to the plethora of terms and functions engineers must master.
Timing is critical in digital audio, ADC's and DAC's must be perfectly synchronized to transfer audio over a network. Click to enlarge.
The IT mantra is “automate, automate, automate”, so IT router manufacturers have developed systems to automatically route packets through networks to improve resilience and data integrity should routers fail. As routing algorithms and protocols become more efficient, they tend to become more vendor specific and the “openness” of network operations becomes more distant, effectively increasing complexity and reliance on specific vendors.
Perfectly Timed Clocks
As networking complexity becomes more apparent, engineers need to specialize more on specific vendors’ equipment, resulting in network engineers being specifically trained on one manufacturers design, sometimes one specific model.
Audio engineers do not compromise on timing, they go to great lengths to guarantee the safe arrival of every audio data bit, coherent and perfectly timed to the sampling clock. Even the loss of one bit can be catastrophic for an audio mix. Unfortunately, IT networks do not have anything like the same respect for timing. IT has its roots in banking and therefore favors data integrity in place of timing, hence protocols such as TCP/IP. These simply do not work in broadcast television as the delays caused by TCP increases latency to unacceptable and unusable levels.
Wheatstone has developed a unique solution to these challenges with their expandable Blade system. An entry level solution might consist of one or two, 1RU Blade I/O access or specialty units that make up the WheatNet-IP audio network and one or two IP audio consoles. Blades come in different models, allowing for Audio-IP, Analog, AES, MADI and SDI inputs and outputs that provide the full array of audio expected in a studio, from mic gain inputs, to mixing, mix-minus creation and aux sends and returns.
Engineers must understand the intricacies of IP networks otherwise they could find IT engineers are measuring protocol speeds when they want line speed measurements.
Blades can be controlled via an automation system, Wheatstone IP audio consoles or virtually anything that relies on software applications. Unmanned studios benefit from this especially, as microphones and other elements that feed into Blades can be controlled from the network’s broadcast center. Guests aren’t intimidated by controls while the sound engineer can get the best sound out of the microphone, for example.
As studios and workflows expand and require more audio sources and destinations, more Blades can be added. Each Blade is a point on the network for ingesting audio and controlling, mixing or routing audio, with full and equal access to the other Blades, consoles and other elements in the network. The stroke of genius with Wheatstone’s design is their autodetection and configuration.
When a new Blade is plugged into a network, it is automatically detected by all the other Blades and added as an access point on the network. No loading of config files or entering data through front panel controls is needed.
All Blades are aware of each other, and have exchanged configuration data. Sound engineers can see the sources and destinations of every Blade on their console, which makes routing of audio and control simple and fool proof. There is no need to raise a help-desk ticket with IT or complete a change-control form every time an engineer wants to add or remove a Blade. It just happens automatically – the ultimate plug-n-play.
Although systems such as Wheatstone’s Blades abstract away the complexities of the underlying IT network, sound engineers must still be aware and understand how IP networks operate, especially when it comes to timing.
IP brings flexibility, better efficiency and greatly improved workflows. Vendors are really starting to see beyond the IT model and applying the benefits of IP to broadcasting systems.
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