Extreme Studio Networking at Clear Channel Seattle
Putting it all together
A lot of equipment needed to come together to make the plan happen.
IP88a Blade access points and E-1 and E-6 control surfaces left the Wheatstone factory in New Bern, NC, labeled and preconfigured for installation. Blade IP access units have the Linux operating system built in, with GPIO, all of which needed to hook into the audio grid. Some were set up to handle all digital I/Os, others analog only I/Os, and others were a combination of digital and analog I/Os with mic inputs.
While equipment was en route, studios were networked together through CAT-6 cable. Large as this network is, gigabit edge switches were used to aggregate the Blades in each studio, and each of the 20 switches was then connected to a core switch. Four Cisco 3750G core switches are stacked together in what Cisco calls their Stackwise technology to spread redundancy over four switches. For extra protection, each switch has separate, redundant power supplies.
All furniture was custom made by Studio Technologies, which it shipped to the facility with some light assembly required. As each studio was built out, engineers dropped in control surfaces and hooked up IP88a Blades as needed. Initial testing was done before moving over equipment from the old studio prior to the final switchover.
Clear Channel engineers and contract engineers were brought in from all over the country to help wire the new facility and make the switchover in small steps. Some had never worked with AoIP before, and it was "learn as we go" for the most part. The deadline was pressing, the coordination of details was mind-numbing, and the hours were long. At one point the team was so dogged tired, it took hours to troubleshoot a simple error: Someone had transposed an XLR wire.
When it was all said and done, the facility ended up with more than 77 access points, each with 16 inputs and 16 outputs -- or more than a million crosspoints feeding all 21 studios with soft logic I/Os comprising 4,928 elements and hardware I/O logic of 924 elements. It's a fast operation. One gigabit/second is shuttled throughout, so there are no quality of service (QoS) issues; there's no need to prioritize audio. Fortunately, gigabit Ethernet hardware, which offers point-to-point audio latency of less than two milliseconds, has come down significantly in price in the past five years.
If it's on the grid, it's as good as an arm's reach away anywhere in the facility -- and sometimes outside the facility. If the weekend jock forgets to leave fader no. 6 up for the Saturday evening show, for example, all the engineer has to do is log into the station's network through a laptop and change it with a couple of clicks of the mouse. It's an easy way to handle all sorts of station upsets and operations from home without ruining an afternoon BBQ or letting the beer get warm.
- continued on page 4
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