The advent of digital networks for audio in stadiums has contributed significantly to the rise of audio’s importance and economic impact in venue operations. In modern stadiums, few systems command as much capital as audio. Audio is the second-largest technology expense behind LED displays. Along with video, it has become a defining element of the stadium experience — from emotional energy to the commercial weight of sponsorship activations, premium environments, and broadcast presentation.
Since its origins, bringing clear, understandable projection of voice and sound to large, widely dispersed crowds has been an ongoing challenge. Single sets of speakers in one location cannot adequately support the audio needs of a large venue. In response, many stadiums looked to upgrade their audio by deploying networks of dispersed speakers.
However, that had its own set of problems. Distortion created by time delays and echoes and loss of signal strength are just two of the transmission issues characteristic of analog system cabling. The massive costs coupled with time-consuming deployment of installing these networks compounded the issues.
Then came the 1990s and 2000s. Those two decades brought dramatic improvements for stadium audio, with the biggest jumps coming in the field of converged networking. As the Internet and associated Internet Protocol (TCP/IP) networks started to proliferate rapidly, a set of innovators developed ways to enable Ethernet networks to carry audio signals — a breakthrough that would eventually change the entire business of large-venue audio.
But even as IP-based audio systems are entering their third decade of existence today, there are still large gaps in knowledge about IP-based audio systems. This is largely due to the lingering business resistance of moving audio signals to shared stadium IP networks. To help understand what’s next for stadium audio, including how better business decisions can be made about their deployment and operation, a look at the evolution and impact of IP-based stadium audio is key.
How did IP-based audio transport come to be?
While sports stadiums were mainly sticking with analog audio networks in the late 1980s and early 1990s, the Internet networking revolution was taking off outside the venue walls. During this time, the standardization of the Internet Protocols (including TCP/IP) for networking spurred the development of new networking equipment like Ethernet switches. This new equipment greatly simplified and increased the power of business networks.
The networking world benefitted from this change, which spurred competition, supported innovation, and drove overall connectivity prices down. Networks of relatively inexpensive PCs and servers replaced the costly mainframe systems of old, and fostered even more innovation and competition on the software side of the business as startups developed new ideas and productivity programs to fit the new paradigm.
In 1996, the stadium audio world was introduced to the world of IP-based networking through the introduction of a product called CobraNet, which allowed users to transport multi-channel digital audio over standard Ethernet. Developed by a Boulder, Colo.-based company called Peak Audio, CobraNet was developed to solve the limitations of analog audio in large-scale professional installations.
While it was a revolutionary product for its day, not many people at the time understood why anyone would want to run audio over a shared network. But the product’s immediate, large business benefits soon became apparent, and started a small landslide of stadiums moving to IP-based audio.
What were some of the inherent analog-network issues that CobraNet solved?
- Eliminating degradation: Analog signals can suffer from electromagnetic interference, crosstalk, and high-frequency loss when sent over long distances. Moving to CobraNet’s digital Ethernet-based system ensured audio integrity remained consistent regardless of the distance between devices.
- Flexible Routing: In an analog system, changing a signal path required physically rewiring the cables involved in a setup. The network-based approach of CobraNet enabled flexible routing and processing of audio signals across an entire venue. Inputs and outputs could be dynamically reallocated without running new physical cables. This made system design and network changes much easier to manage in a large, multi-use venue like a stadium that hosts different types of events like concerts, shows or games.
- Reducing Costs: By using off-the-shelf Ethernet equipment including switches, hubs, and cabling, stadium managers found they could save between 15 and 75 percent on material and labor capex costs when compared to more traditional analog setups.
- Simplifying cabling: Before CobraNet, stadium audio setups required massive amounts of point-to-point analog wiring, with bulky, expensive, and heavy multi-channel “snakes” and patchbays needed to route every audio signal. CobraNet allowed stadiums to replace these bulky cables with a single Category 5 (Cat 5) cable, which could carry up to 64 channels of uncompressed audio in each direction.
- Streamlining and increasing the power of mixing boards: The simplified cabling of CobraNet also eliminated the need for hundreds of individual copper-cable connections to a large analog mixing board. For digital mixing boards, CobraNet was a critical enabling technology that allowed them to scale for massive live productions. With CobraNet interfaces, digital consoles could communicate with remote stage boxes and amplifiers across an entire facility without signal degradation. Mixing boards could also be much smaller in size, as they were able to replicate the performances of analog outboard gear like compressors and graphic equalizers with chip-based functionality.
CobraNet’s first commercial deployment was for Super Bowl XXXI’s halftime show in New Orleans in 1997. After that, CobraNet was quickly adopted by many stadiums. Its inclusion as part of the technology stack at Nissan Stadium (then called Adelphia Coliseum) for its opening season in 1999 showed how CobraNet had quickly become a standard for new venue construction. The sheer common-sense cost and performance benefits of a networked approach led to thousands of deployments of CobraNet through the early to mid-2000s.
Network effects continue to change and improve IP-based audio
If CobraNet was responsible for changing stadium audio forever, it also fell to the competitive environment it helped create. After Cirrus Logic purchased CobraNet developer Peak Audio in 2001, the company did not significantly improve CobraNet. Meanwhile, a host of competing products started to emerge, all making use of the underlying power of IP networks.
Even though CobraNet represented a huge leap in performance and functionality from previous analog audio systems, the protocol did have some limiting factors. Since it transferred data using data link packets, a Layer 2 protocol, CobraNet was mostly limited to single-premise deployments since its packets could not travel through routers. CobraNet also was written to make use of 100Mbps “Fast Ethernet,” which was a limitation because Ethernet speeds increased to gigabit levels with continued innovation.
Other drawbacks, including a limited channel count and fixed latency rates that were too slow for some real-time applications, led to more innovation from others on the audio networking front. In 2006, an Australian company called Audinate — formed by former Motorola research employees — launched Dante (an acronym for Digital Audio Network Through Ethernet), which would emerge as the market leader, a position it still holds today.
Unlike CobraNet, Dante operated at the Layer 3 network level, so it could run on commodity Ethernet switches with no special hardware requirements. Since Dante packets could be routed, venues could now support communication between different networks by routing packets across a larger or wide-area network.
Dante also supported higher channel counts per link, as well as configurable, lower-level latency. Both of these attributes worked well in stadium audio situations, which were now calling for multiple audio inputs and outputs, as well as real-time, live performance synchronization of audio broadcasts.
Just as the more-nimble and less-expensive networks of PCs and servers eventually rendered IBM mainframes obsolete, and as Voice-over-IP technology eventually replaced the closed voice networks of Ma Bell, the innovative power of IP network technology is now becoming part of the stadium audio landscape.
By adapting to changing user needs and embracing network technology improvements, Dante was able to supplant CobraNet and become the market-leading audio protocol. But the venue audio industry continues to innovate, with industry-wide interoperability efforts like the development of the AES67 protocol ensuring that future stadium audio needs not be tied to a single vendor’s offerings.
Though islands of analog audio network systems may still exist across the stadium world, the continued confirmation of real-world benefits brought by IP-based audio are being realized by more and more venues. In addition to the aforementioned capex and opex benefits realized by standalone IP-based audio deployments, a new trend is emerging under which stadium audio networks become part of a single, converged venue IP-based network, allowing for even greater reductions in purchase and operational costs. The good news for venue owners and operators is that if history is any guide, the innovation and competition fostered by the standards-based IP networking approach will bring continued benefits for end users.
