The best protocol is not the one everyone talks about. It is the one your team can operate, expand and explain. If your audio network only makes sense to the person who installed it, your church has a long-term problem.
Audio is king. Audio is the undisputed number-one media concern for churches, regardless of worship space size. The congregation must be able to hear the pastor’s sermon and the worship leader’s voice clearly and without distraction. Because of the importance of audio to houses of worship, problems can and will arise when opportunities present themselves to expand or purchase new equipment.
The wrong protocol assumption can turn a smart upgrade into an expensive headache.
One of the main problems I observe when churches purchase a new audio console or other audio-related equipment concerns the use of digital audio protocols. Sometimes, a new console purchase causes issues with integrating it into the current audio infrastructure. Other times, an expansion of I/O capability or networking causes problems and frustration. To avoid these issues, a church technical leader should help their leadership by understanding the digital audio protocols in use by most major audio manufacturers today. The list of digital audio transport protocols is long: AES50, AES67, AVB, Dante, EtherSound, MADI, Milan, Optocore, NDI Audio, Q-LAN, Ravenna, SLink and others. Rather than cover every option, we’ll focus on the protocols church production teams are most likely to encounter.
MADI, AES50, SLink, AES67, Dante, AVB and Milan all move audio. That does not mean they move it the same way.
Multichannel Audio Digital Interface (MADI, also known as the Audio Engineering Society AES10) is an older protocol, first introduced in 1991 and updated in 2008, that allows 64 channels of uncompressed digital audio at 96 kHz sampling to be transmitted via a single coaxial or fiber-optic cable. Unlike Ethernet-based AoIP (Audio over IP, like Dante), MADI is point-to-point audio streaming with zero latency and absolute reliability. It doesn’t require complex IT switches or IP programming. Because it is an open standard, major manufacturers provide expansion cards for connecting to MADI networks. Its major use today is for direct console-to-console splits, connecting legacy stage boxes, and feeding multi-channel broadcast or mobile recording rigs.
AES50 is an open standard protocol developed by the Audio Engineering Society that transmits high-resolution, multi-channel audio and clock data over standard, shielded Ethernet cables. A single run of Cat5e or Cat6 shielded cable with AES50 can span up to 328 feet (100 meters) between connection points. AES50 transmits up to 48 bidirectional channels at a 48 kHz sampling rate or 24 bidirectional channels at a 96 kHz sampling rate. Unlike Dante and other Ethernet-based networks, AES50 cannot route through standard Ethernet switches. It is a point-to-point protocol. Some consoles use AES50 to connect the front-of-house console to stage boxes, replacing bulky, analog, multi-core snakes with a single Ethernet cable.
SLink is a proprietary digital audio protocol for Allen & Heath SQ series, Qu series, and dLive mixers to connect to its stage boxes and expanders. It offers extremely low latency and supports cable runs of 328 feet (100 meters). It is used to automatically adapt and transmit hundreds of channels of uncompressed digital audio and control data over a standard Cat5e (or higher) Ethernet cable. It’s important to note that SLink is not a single audio protocol but rather a universal port that automatically switches to communicate with whichever Allen & Heath devices are plugged into it. For example, the SLink port will run one of three protocols:
•gigaACE – can transmit up to 128x128 channels at a sampling rate of 96 kHz. This is used for high-end consoles like the dLive, as well as its stage boxes and front-of-house racks.
•DX – can transmit up to 32x32 channels and is designed for connecting Allen & Heath’s DX series of stage boxes and expanders.
•dSnake – can transmit up to 40 inputs and 20 outputs at a sampling rate of 48 kHz. This is primarily used for connecting legacy Allen & Heath stage boxes or personal monitoring systems.
It’s important to note that SLink, along with gigaACE, DX, and dSnake, is an Allen & Heath-only protocol and does not offer interoperability with other manufacturers.
MADI, AES50, SLink, AES67, Dante, AVB, Milan and others each solve audio transport problems differently.
AES67, developed by the Audio Engineering Society, enables different Audio-over-IP (AoIP) networks to communicate with one another. It acts as a bridge/translator by establishing universal rules for clocking, streaming, and transport, allowing previously incompatible protocols like Dante and Q-LAN to communicate with one another. It supports uncompressed audio at sampling rates of 44.1 kHz, 48 kHz, or 96 kHz with 16- or 24-bit bit depth. Low latency is also inherent to AES67, which makes it especially useful for professional audio production environments. High channel counts are also available with this protocol, enabling the simultaneous transmission of hundreds of audio channels over a standard gigabit network. Because AES67 is an interoperability standard rather than a standalone audio network protocol, any console running on a compatible core platform can use it. Compatible core platforms include Dante (Yamaha was an early adopter of AES67 for live sound), Q-Sys (QSC), Ravenna (used by Neumann, Genelec, Riedel, and others), and Livewire+ (used by Studer, Yellowtec, and Deva Broadcast, among others).
Knowing whether a protocol is open, proprietary, point-to-point or networked can shape the whole upgrade conversation.
Dante (Digital Audio Network Through Ethernet) is a proprietary protocol developed by Audinate that routes uncompressed, multi-channel, low-latency digital audio over Cat5e and Cat6 cables. Dante is a very popular protocol for the live sound and house of worship market. Like other digital audio protocols, Dante uses a virtual patchbay, where devices connect to a network switch, and routing and patching are managed via computer software. This allows up to 512 bidirectional audio channels at 48 kHz/24-bit to be transmitted on a single Gigabit network. Dante has near-zero latency, usually between 0.25 ms and 5 ms, depending on the network setup. Devices are perfectly synced via Precision Time Protocol (PTP), eliminating audible phase issues and dropouts. Dante offers extensive interoperability with over 600 manufacturers across the audio industry.
The final digital audio protocol church technical leaders should know about is AVB and Milan. First, AVB (Audio Video Bridging) is an IEEE (Institute of Electrical and Electronics Engineers) standard that enables the transmission of time-sync’d, low-latency audio and video streams over standard Ethernet cables and switches. AVB has three core function:
•Guaranteed Bandwidth – AVB reserves a specific fraction of the Ethernet bandwidth for media. This means that your audio/video data streams are prioritized on the network, preventing standard traffic from causing dropouts or lag.
•Time Synchronization – AVB ensures all connected devices are synced to a master clock, guaranteeing audio packets are played back in perfect time across the entire network and system.
•Low Latency – AVB keeps the delay to under two milliseconds, even across multiple network switches.
AVB (Audio Video Bridging) is widely used in the professional audio industry because it is an open standard. Unlike proprietary network protocols, AVB allows manufacturers to create AVB-compatible products without paying licensing fees. An AVB network is also self-configuring. It requires very little network admin or IT knowledge. Devices automatically negotiate the network to guarantee reliable performance. Finally, AVB allows for converged networks. This means you can route multiple channels of uncompressed audio alongside standard control data, video, and general internet traffic over the same Ethernet cable.
Here is where Milan (Media-Integrated Local Area Networking) comes in. AVB had interoperability challenges early on when it came out. So, the Avnu Alliance (a group of manufacturing companies working together to create reliable, synchronized, low-latency networks using open IEEE standards) created Milan. Milan is an open, deterministic protocol (guaranteeing data packets are delivered within a precise, predictable timeframe with zero congestion-based data loss) designed for professional audio. Built on top of the IEEE AVB and TSN (Time Sensitive Networking) standards, it ensures guaranteed delivery, zero dropouts, and perfect synchronization of multi-channel audio across different devices. Unlike closed/proprietary protocols, Milan-certified devices from different manufacturers (for example, d&b audiotechnik, Meyer Sound, L-Acoustics) will seamlessly connect out of the box. Finally, Milan does not require complex IT routing or managed switch configurations. It also provides seamless redundancy by supporting dual networks out of the box, enabling instant switching to a secondary stream in the event of a cable failure.\
Digital audio can simplify a church system or complicate it, depending on what already lives in the rack.
So, what does all of this mean for the church technical leader? First, know your current audio system inside and out. Know the signal flow from microphone to loudspeaker like the back of your hand. Know the audio protocol that your system uses. It might be all analog. It could also be a combination of analog and digital, or even all-digital. The important thing is that you know exactly how things move and operate on your audio system. This will help immensely when evaluating new audio equipment and assessing its compatibility with your current setup.
Secondly, know the main digital audio protocols well enough to discuss them intelligently with system integrators, salespeople, engineers and your peers at other churches. If you are buying new equipment, a digital audio-based solution will be presented to you. Make sure you know enough about each protocol to understand how it would interact with your current or even a completely new audio system. This knowledge can save your church money and heartache when deciding about new equipment additions, upgrades, or overhauls.
Finally, be prepared to explain this complicated world of digital audio to church leaders who have no idea about professional audio systems, digital audio, or exactly what you do. I wrote a previous article for Church Production entitled “Talking Pastor-ese: How to Talk to Your Pastor Who Doesn’t Understand What You Do.” (See this link.) In it, I talk about how it’s up to you, as the church technical leader, to take the initiative to learn about the interests and hobbies of your pastor or church leaders. Then, craft your message about digital audio in a way they understand, using their interests and knowledge. For example, if your leaders are car racing fans, explain digital audio in car racing terms, like how Indy Cars and NASCAR don’t race at the same time on the same track. This is like Dante and AES50 on a digital audio network. You can’t have them on the same track.
Knowing how your audio moves from microphone to loudspeaker can make the difference between a smart upgrade and a costly mismatch.
Navigating the world of digital audio protocols can be tedious and confusing. It’s not something to be afraid of, though. Have a learning attitude and teachable spirit. Be willing to put in the time to educate yourself. And most importantly, commit this task to prayer, asking the Lord to help you be the best steward of the ministry and tools He has given you. You’ll be surprised by how much and how quickly you can learn by following these simple steps and how much you can help your church make wise decisions.
