If you have purchased a single piece of digital audio equipment over the past few years, you’ve likely had to consider audio networking when thinking about how it would connect or integrate into your sound reinforcement system. Sure, you could continue using analog audio interconnects, or even AES/EBU or MADI, but the ubiquitous nature of protocols like Dante and AES67 must have you wondering about their benefits. In fact, audio networking has come a long way since CobraNet’s heyday. Not only is networked audio more affordable than ever, it’s easier to configure, easier to manage and within reach of any sanctuary with a reasonable audio budget.
What’s the Advantage?
It is a legitimate question. If you’ve been using AES/EBU or MADI for many years, it’s tough to imagine why you would switch. You’re not alone. While the live event industry has been quick to adopt Dante, the broadcast world has been slower to switch off of MADI because it is engrained in their workflow. Why should you consider audio networking as part of your facility? There are a few key reasons. First, protocols like AES/EBU and MADI are point to point. Audio travels from point A to point B. On the other hand, networked audio opens up flexibility that you never had with point-to-point protocols.
Audio can be distributed anywhere on your LAN (and between LANs if needed). This means that anywhere you have network access, you can have audio distribution as well. Audio can be put on the network and taken off of the network with ease in different rooms or even different buildings, using your existing network infrastructure in many cases. Second, networked audio takes advantage of common off the shelf (also known as “COTS”) networking hardware from companies like Cisco. This allows the audio world to tap into the “economy of scale” provided by networking hardware manufacturers. The switches and cable are relatively cheap compared to AES/EBU or MADI routing gear that would provide similar functionality. Over the next few years as 10 Gigabit switches supplant 1 Gigabit switches, the bandwidth available for networked audio systems will increase dramatically.
What You Need to Know
If you’ve been in the A/V industry for a while, you’ve probably met someone who was new to the business. They always stick out like a sore thumb because they can’t talk the talk and they don’t know the language we speak. In fact, a lot of A/V folk sound the same way to our IT counterparts. I can’t count the number of times I’ve heard audio engineers call networking “voodoo” or “magic.” It is incumbent upon us as A/V technicians to at least speak their language, because we’ll rely on them to help setup and troubleshoot our networked audio system. Having a great relationship with our IT co-workers is essential. IT isn’t that different from A/V after all, and these days they are almost one in the same. “Converged” is a term often used to describe the melting pot that is A/V and IT in 2016. I often tell a story to my students about sitting in a meeting with a major audio manufacturer a few years back. This particular manufacturer mentioned they prefer hiring people with a Cisco CCNA (Cisco Certified Network Associate). In that same meeting, the manufacturer representatives described designing a networked A/V system for a major football stadium with only IT people in the room. That meeting spurred me to learn more about networking, a journey that I feel like I’m only just beginning today. Below is some of the terminology that you’ll want to know and understand in order to “talk the talk” with your IT department. Describing even one of these terms is an entire book chapter unto itself, but if nothing else, this list gives you a place to start:
• Layer 2 and Layer 3 (and the entire OSI model in general)
• MAC Address and IP Address
• Switches and Routers
• Managed vs. Unmanaged Switches
• LAN, WLAN and WAN
• DHCP vs. Static IP Addressing
• VLANs
• Subnets and subnet masks
• QoS (Quality of Service) and Diffserv
Selecting Hardware
Most of the popular audio networking protocols promote the use of “COTS” (Common off the shelf) switches. If you aren’t familiar with that terminology, it could lead you to believe that any switch at your local electronics store is appropriate. In fact, there are some specific criteria for audio networking switches, and it really depends on what protocol you are using. For example, AVB requires AVB compliant switches. Dante, on the other hand, can use a much wider array of available switches, but Audinate and Dante hardware manufacturers specify some basic criteria for what they deem acceptable. Here are some common criteria for Dante
switches…
• Managed Gigabit Switches
• Non-Blocking
• QoS with 4 queues
• Diffserv with strict priority
The Future
Audio networking is a great way to get your feet wet with IP media transport. If you’ve attended any tradeshows over the past few years, you know that IP is sweeping the live event and broadcast industries. In a short five to ten years, IP will replace traditional transport protocols like SDI, MADI and AES/EBU. IP video as an SDI replacement will be the next big hurdle that we’ll need to overcome as church technicians, so be prepared — because IP isn’t going away anytime soon.
Vince Lepore is the technical director at St. Luke’s United Methodist Church in Orlando and teaches live production at Full Sail University.
