Music is Everywhere at WTMD


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Studio B has an Allen & Heath GM24 console with FireWire option. The FireWire allows for a single A/D conversion of performance studio sources. After the A&H, signals pass to a PC, equipped with recording software and the Axia MultiChannel Driver that allows those sources to appear on the LiveWire network. A real effort was made to keep it all digital, all AES, all 48kHz, all AoIP, all structured wiring throughout the facility. [For more on structured wiring, see page 3 or this article.] I believe we achieved that goal.

Structured wiring

The WTMD facility has approximately 40,000 feet of CAT-6 UTP cable as structured wiring that handles every source-destination path that could possibly be carried over such media. Except for the mic lines, 5.1 powered speaker runs and monitor returns in studio B, there are no traditional STP audio runs between rooms. Instead, each room has 24 runs of CAT-6 UTP from TOC and terminated in a patch bay. There is a run of RG-6QS to each studio for CATV and from the roof for various reception concerns.

Connectivity was key in all studios to provide maximum flexibility. Photo by Jack Dana.

Connectivity was key in all studios to provide maximum flexibility. Photo by Jack Dana.


The type of cabling to be used (CAT-5 or 6) and how such is terminated (patch panels) form the basis of structured wiring. All this is defined using standards that appear in the National Electrical Code, ANSI/TIA, BICSI etc. We then interconnect devices. The core wiring — the infrastructure — never changes. After installing the core wiring early in the project, we have yet to pull a new wire between any two racks or studios. Patch cords are used to go from patchbays to nodes. Where necessary, Studio Hub+ compliant adaptors for audio-over-Ethernet (AoE) are used. While the structured wiring at WTMD supports Studio Hub-enabled products, the same wiring is supporting data networks, Avocent KVM sharing and extension system, USB-over-Ethernet extenders for touch screens, NTP/POE LED clocks, LVDC LED on-air lights, Valcom speakers in common areas and video signals using HDMI to HDBaseT converters. There are some instances where TTL or RS-232 were necessary, and carried over the same wiring.

Nothing goes between racks, each rack has a 16- or 24-port CAT-6 STP patch bay with the “other end” at two patch racks that terminate all wiring and switches. The flexibility benefit is obvious. In a university setting however, buy-in from the university IT department can be a real challenge. I did a network diagram of the entire plant, and I asked for the university wiring specification. The studio wiring spec was derived from that document. The rack that houses the studio concentration of patch bays also houses various runs to other offices in the suite, and a 48-port tie to the university LAN. Because the design conforms to the university specification, it made it possible to have their usual vendors quote all of that wiring, the switches and servers. Having that infrastructure then allowed us to accommodate several curve balls.

After all the budgeting and planning was done, we were told that the studios had to vacate almost two months sooner than planned! And we would have to move the studio on a weekend when a fund drive started. Yikes? Nope. We purchased an Axia Radius console. A temporary studio was built in two days, and two patch cords connected it. One cord ran from the console AES output, to a wall jack to route to TOC. At TOC, AES audio was connected to a loaner Tieline Bridge-IT connected to the campus network. The companion end of the Bridge-IT at the old studio was connected to the STL. We had to continue feeding the old STL and transmitter until the mast and antenna were erected. The second patch cord allowed an Axia node to be routed from an RJ-45-equipped TV wall plate at the lobby. Since the node uses power-over Ethernet (POE), all we had to do was connect mic and 600Ω headphones to do pledge breaks. Soon thereafter, it became necessary to move production and an existing Enco system to the new site as well. Yes, we moved and operated the station from the new site while building the new site. The presence of so much RJ-45-ready infrastructure made it possible to reconfigure many systems with little planning as needs changed.

- continued on page 3



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