May 2016

Industry Point Of View
IT... IP... Network...
AV over IT won't hurt you.
Article By Rob Ziv, CTS, Almo Professional A/V
Article reprinted from Sound & , March 2016

  One hurdle faced by integrators is gaining confidence within the world of networking in general.

Like sunrise to vampires and mice to housewives, these words oftentimes strike fear into the hearts of AV Integrators. Well, it's time to pull the covers from over your head and climb down from the chair, because AV over IT won't hurt you.

IP-based signal distribution provides advantages over other forms of signal distribution in terms of flexibility, capability and, in many cases, cost. Manufacturers realize that some AV integrators are still concerned over working with IT-based solutions and have stepped up the resources to reduce perceived barriers to entry and simplify what was once an anxiety-producing experience. Today, AV over IT is often easier and faster to implement, more flexible and lower cost, with higher profit potential than the old-school options.

IP-based solutions allow for a single Cat5e/6 cable to carry dozens, sometime hundreds, of signal paths over a single cable. This reduces termination costs, cabling costs, conduit utilization and potential points of failure. Don't worry, redundancy is available in most solutions so that, if a single cable fails, you don't lose all your signals. Capacity and flexibility are increased because limitations are oftentimes determined only by available bandwidth and the location of a network jack. This is very different from other solutions that might require oversizing or forklifting a matrix switch just to add one more source or output. IP-based solutions also reduce the distance limitations and signal-loss issues associated with conventional signal distribution methods. Fiberoptic connections between switches allow a network to cover a very large physical area.

Let's look at a situation where conventional systems fall short and an IP-based methodology may simplify our project: We have a retrofit of a local city hall where they need to upgrade audio within council chambers along with several courtrooms. Most audio is routed to a centralized room within the facility and then distributed to multiple locations as necessary. System upgrades call for more microphones and sources than before. In a conventional scenario, every individual microphone cable or bulky multi-core snake would have to be pulled through conduit to the equipment room, along with any other cables required for the project. However, this is a historic building where conduit capacity does not exist for the additional mic cables, and access for new runs is limited, if not impossible. How can an IP solution help? Dante Controller to the rescue.

Dante was launched by Audinate in 2003 to provide a complete end-to-end audio networking solution comprised of tools for equipment manufacturers and end users, software for design and control, and support to facilitate adoption and use. The goal was to create a solution that is "Easy to Integrate, Easy to Install and Easy to Use."

If growth is any measure of how Dante has done in meeting its objectives, about 300 manufacturers now provide Dante-enabled solutions, with more than 30,000,000 audio channels of Dante in use. Dante is found in systems ranging from basic conference rooms to large-scale installed and touring production systems. Some of the factors that have contributed to this adoption include:

• Dante Controller is the flexible software that is used to manage, control and route audio in all Dante systems, regardless of manufacturer. For example, every device can be given a name that makes sense instead of looking at IP addresses to route signal. Routing within Dante Controller is accomplished using point-and-click cross points similar to other non-IP based matrices.

• Connect a Dante-enabled device anywhere on the network and it is automatically recognized in Dante Controller.

• It is compatible with existing networks and off-the-shelf networking equipment.

• It offers end-to-end solutions with consistent implementation practices across manufacturers.

Audinate created a complete solution that goes beyond creating a protocol and an equipment interface to include design and management tools (i.e., Dante Controller) and support. Equipment is available covering the entire signal path from microphones to speakers. Audinate oversees everything from the chipsets used in Dante-enabled devices to the software interface for Dante Controller. This allows for consistent implementation of the Dante elements of a project across multiple manufacturers and platforms.

With IP-based signal distribution, individual cables run to a network switch within the room, then a single Cat5e/6 cable runs to the audio DSP. This simplifies long cable pulls, minimizes conduit utilization and reduces installation cost while improving system flexibility.

Dante endpoints can take your favorite individual microphones' standard XLR output and converts them into a Dante signal on an RJ45 connection. These endpoints are available in several form factors, such as wall panels, under- and in-table boxes. All the endpoints in a room are connected to a single PoE network switch. PoE allows the endpoints to deliver phantom power to the microphones. A single Cat5e/6 cable carrying all the microphone signals runs from the switch back through the existing conduit to the equipment room. What may have required dozens of cables is now reduced to one. 

Conventional wiring of individual mics to a centralized DSP requires individual cables or bulky multicore cable runs.

The end of the cable in the equipment room is connected to a Dante-compatible device. This could be an auto mixer or DSP that has Dante capability built in, or a Dante off-ramp that takes Dante and converts it to a conventional signal type to connect to the unit of your choice. However, with about 300 manufacturers now supporting Dante, chances are you are just going to connect via Dante directly to the device of choice. Audinate provides CTS RU-certified training classes on Dante, which can go a long way to helping someone become comfortable with the technology. However, once you spend a few minutes inside Dante Controller and see how intuitive it is, preexisting concerns over IP-based signal distribution will most likely fade.

Dante is not the only kid on the block. AVB/TSN, CobraNet, AES67 and a variety of manufacturer-specific methodologies are also available. However, Dante is the only widely adopted end-to-end solution that provides a consistent user experience across multiple manufacturer platforms.

Dante supports up to 512 channels in and 512 channels out on a single system with mixed sample rates up to 192 kHz at 32 bits. Audinate recommends using network switches that fall in the small business category, such as a Cisco SG300. If you use the recommended switches and are keeping Dante on its own network, then creating a Dante-based system requires almost no more networking skills. Plug the devices into the network, power them on, fire up Dante Controller and you are pretty much ready to start routing signal. It really is that easy. If you do need to run Dante over a network where there is other network traffic, then well... you may need some help configuring a switch and communicating with IT.

Just a little geek-speak, peek behind the curtain: Dante uses Voice over IP (VoIP) Quality of Service (QoS) to prioritize audio packets over other data on the network. Sync is maintained using PTP (Precision Timing Protocol). The packets themselves are sent using UDP instead of TCP. Although TCP is generally considered more reliable than UDP, UPD is generally preferred where speed is critical, such aa real-time audio. UDP uses less bandwidth due to the smaller packet headers and the lack of return confirmation from the receiving device.

To ensure that a reliable connection is still available between devices, a handshake occurs between the receiving channel and sending channel when a subscription is first made in Dante Controller. Latency is set to a fixed amount between 0.15 to 5ms, depending on the system size. Note that 5ms is typically only used for troubleshooting, keeping real-world latency to 1ms and oftentimes less. During the initial handshake, the devices also check to see if latency has been set long enough between devices.

Dante has made audio over IP relatively easy and consistent across manufacturers. With video, things get slightly more complex. Although there are multiple IP-based methodologies for video (with audio), there has yet to emerge a widely adopted end-to-end solution that provides a consistent user experience across multiple manufacturer platforms.

What about H.264 or AVB. Don't these qualify?

Perhaps, to some degree. But depending on the manufacturer, there are multiple methods of implementation once you leave the source. Unlike Dante Controller, this keeps them from providing a consistent integrator-friendly interface independent of the chosen manufacturer(s). For this reason, it is probably best to review the various options for video at another time (besides, it's almost time for you to get back to work).

One hurdle faced by integrators is gaining confidence within the world of networking in general. Manufacturers have stepped up their resources in this area because they recognize this will help them gain market share. I'm not suggesting that this is Cinderella's castle where the manufacturers' little mice will do all your cooking, cleaning and mending. But some will even go so far as to work with an end user's IT department on your behalf.

Alternatively, many of the primary benefits of AV over IP can still be attained through creating a dedicated network for AV, and this may be worth consideration. Yes, you will lose the benefits of using existing cabling and network drops. But it simplifies the networking aspects overall to the point where the process resembles deployment of a conventional system and still maintains the other core benefits of AV over IP.

Enjoy the Music.com would like to thank Sound & Communications for allowing us to reprint this article. Please visit their website at www.SoundAndCommunications.com.


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