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CPR’s Prognosis Is Good With Axia [In]Fusion

Last summer, it became clear that the audio routing system at the heart of the Colorado Public Radio statewide network was failing, but this spring, CPR breathed new life into its air waves

In the world of electronics, 12 years can be a lifetime. Systems fail, technology changes, and the �state-of-the-art� system you commissioned is at its end-of-life.

The CPR Bridges Broadcast Center is located at the Denver Tech Center in Centennial, Colorado

Last summer, it became clear that the audio routing system at the heart of the Colorado Public Radio statewide network was failing. Multiple attempts to revive it proved fruitless. The equipment was dying. This spring, CPR breathed new life into its air waves.

Colorado Public Radio was born 46 years ago in a broken-down old house on the campus of the University of Denver. It was run by students back then and called KCFR. It was a tiny, news-only, 10-watt station, the first non-commercial public radio station in the city.

Ryan Warner of CPR News busily readying a story.

In 2004, KCFR moved to our current location, south of the Denver Tech Center in Centennial, Colo. By then, we had acquired KVOD, a classical format, and re-branded to become Colorado Public Radio. Today, the Colorado Public Radio family includes three separate services: CPR News, CPR Classical and CPR�s Open Air, a new and independent music format.

Our network reaches more than 470,000 listeners each week over a statewide web of 13 stations and 17 translators. The source audio for our network originates from our Tech Center home base, which houses eight on-air studios, one live performance studio, five voice-tracking sound booths and the hub of our satellite and STL operations. One additional on-air studio is located on the western side of the Continental Divide in Grand Junction, Colo.


The Colorado Public Radio facility is home to CPR News, CPR Classical, and CPR Open Air

Now, with the integrity of our network at stake, the audio router, and by extension, the entire audio chain, had to be rebuilt. However, changes in technology over the lifecycle of the existing system required more than an equipment upgrade. It required a paradigm shift from the old world of TDM routing to the new world of audio over IP.

The heart of the new system would no longer be a traditional audio router, but an IP-based data switch. This created concerns about the compatibility of the new system with existing audio chain equipment and with current and future automation systems. There were also concerns about latency in switching and the operational impact that might create.

To address all of these concerns, Vice President of Engineering Dean Phannenstiel chose Axia.

�We had existing Livewire options with our PRSS equipment, Nautel transmitters and Program Delay Manager boxes� Phannenstiel said.

The Livewire protocol also integrated well with the current RCS Nexgen automation system and with the new Zeta system, which will replace it later this year. Phannenstiel worked with Greg Dahl of Second Opinion Communications to determine which Axia consoles best suited our studio needs. He also looked for advice on Axia user forums and Pubtech and spoke with engineers at other stations currently using Axia. There were definite advantages to Axia that appealed to him.

Judy Bandstra contemplating the finishing touches to one of the 14 studios of CPR
Photo credit: Ervin Coffee

In the end, Phannenstiel�s decision relied as much on gut feeling as it did tech specs. �I liked the look and feel of the Fusion,� he said.

After extensive consultation with Dahl, and the CPR Production and Engineering teams, Phannenstiel decided on one Power Station, paired with a 16 fader Fusion console, per studio. Each console is configured with 12 faders and a monitor module. In place of the old Telos hybrids, there is an Axia VX engine, which integrates with our existing Shortel VOIP system, and a two-line Vset phone in each studio. One of the operational advantages to this system is that it automatically routes the mix-minus to the appropriate destinations.

Each studio is tied to the rest of the Livewire network through the new nexus of the system, the IP switch. Phannenstiel knew that because it could become a single point of failure, the switch had to be robust: �We had to build it to be nearly bulletproof.�

He selected the Cisco 4510 with fully redundant processor boards, switch blades, power supplies and its own UPS. All studios tie back to the switch through redundant Cat6 lines.

The new Fusion consoles were considerably larger than the old boards, so the existing studio furniture needed to be replaced or modified. Rod Graham, owner of Graham Studios, built the original cabinets in 2004. We contacted him and asked if he could modify the furniture to accommodate the new boards. He agreed. His team prebuilt some new desktops at their shop and then made several trips to our studios to install them. They modified the other desks on site.


We completed the project in three phases.

The business end of the Axia Fusion engine, with wiring completed
Photo credit: Ervin Coffee CPR Engineer Judy Bandstra adding final connections to an Axia fusion engine installation
Photo: Dean Phannenstiel

First, I documented the existing system using Autocad. Every wire and every piece of equipment in our system was catalogued and illustrated in signal flow, location and elevation drawings. That process took several months, but it created a roadmap to guide us in building the hybrid system we would need to bridge the gap between the old TDM router and the new Livewire system.

Then, we added Axia xNodes at strategic points within the audio chain. That enabled us to seamlessly remove portions of the old system when the new Axia system was brought on line. It also provided an emergency bypass audio path for all sources to the program DA in case of a TDM router failure. We integrated a total of 16 analog, digital and GPI Axia nodes into the audio chain, tying the old and new systems together.

Next, we focused on the studios. Before we decommissioned the old ones, Phannenstiel and broadcast engineer John Van Milligan preconfigured the new engines.

One of CPR�s 8 on-air studio, featuring an Axia Fusion console, Telos VX, and furniture by Graham Studios
Photo credit: Ervin Coffee

�The Powerstations were configured in both a control room/studio configuration as well as a standalone studio configuration based on what profile was selected. We added additional profiles based on each of our format�s needs in addition to some general purpose voice tracking and interview profiles. We created stacking events using Axia Pathfinder to map a specific button on the board to arm the board for �Live� for any format based on the profile selected. We also created �next event� buttons for playback control for the automation audio servers,� Phannenstiel said.

Our eight studios are paired into four sets, according to station format. To cause the least amount of disruption to operations, we spread the buildout over four weeks, taking one pair off line per week.

Our Engineering team worked together to decommission and rebuild each studio. I finished up the final wiring and documentation, and Dahl returned to help with the final configuration. Over the course of the project, there were some studios running on the old TDM router, and others on the new AoIP system. Because of our phase-one hybrid build, the transition was seamless. At the end, when all of the studios were fully converted to the Axia system, we decommissioned the old TDM router.

One of many racks in the CPR facility holds DEVA 8008 silence sensor/backup audio players, Broadcast Tools ADMS 44.22 analog/digital matrix switchers, and Axia xNodes
Photo credit: Ervin Coffee

Once the new system was online, we addressed the initial concerns about switching latency. Because of the nature of the system, some delay was unavoidable, but Van Milligan found a work around for most issues.

�I knew it was not going to be a show-stopper,� Phannenstiel said.

Studio guests can�t listen to the final program audio feed to air because it contains too much latency. However, studio headphones and microphones, set to live mode, show no perceivable delay. The biggest concern in moving to the new system was how well end users would adjust to the change. That has not been an issue so far.

�We�ve really had nothing but positive feedback,� he said.

In the technical operations center, we installed an Axia Soft Surface virtual control panel and an Axia 17 button smart panel to assist with confidence monitoring and control. The panel �was configured using Pathfinder to have hot buttons to quickly route predefined sources to air for any of the three services, as well as displaying which studio is armed for live and button color changes for active routes and live studios. To prevent accidental button pushes on the panel, we created a special �unlock� button that needs to be pushed before a hot button can be activated,� Phannenstiel explained.

In the engineering shop, we added an Axia X-select routing panel and a QC station to allow us to monitor any audio signal in the system. We also installed Pathfinder Pro software on redundant servers to give us virtual routing control of the entire system.

Part of the studio upgrade required changes in the furniture.Graham Studios changed out many of the studio countertops, as seen here.
Photo: Dean Phannenstiel

The current and final phase of the project is upgrading the voice tracking booths. These are heavily used to produce on-air content, but they are currently equipped with old analog mixers with no interconnectivity to the main system. The booths are paired; two for music, two for news. A fifth standalone music booth piggybacks the live performance studio. It will have a QOR.16 and an IQ eight-fader console. For the paired booths, we are installing an Axia QOR.32 engine with one DESQ six fader console in each booth. The QOR engine automatically partitions its I/O to accommodate the two consoles. The news booths will also have a one-line Vset hybrid phone. All of the voice booths will now tie into the new Livewire network through the Cisco switch.

When the final phase is complete, we will once again have a fully �state-of-the-art� audio chain, from microphone to microwave.

The gradual integration of this new technology into our core of operations has helped CPR operators and engineers build confidence in the AOIP concept of system architecture. There is no guarantee of longevity in the life of any system, but with the infusion of new technology, there is hope. CPR now has a system more robust, more flexible, and more user friendly than the one that came before it. After 12 months of major surgery, the prognosis is very good.

Judy Bandstra has been a broadcast engineer for nearly 20 years, having spent the last year and a half with Colorado Public Radio.� Prior to that, she spent seven years in the U.S. Navy as an RF technician.