Music is Everywhere at WTMD

January 4, 2014


WTMD-FM/HD, owned by Towson University in Towson, MD, recently commenced operations from a new 8,000 square-foot studio and co-located transmitter facility. Having moved literally from the basement to a high rise, this was a big deal for everyone involved — from staff to vendors, administrators, listeners (of course), and the visiting bands. Bands are a big part of WTMD: There is a daily effort to showcase up-and-coming musical talent. The design enables music production everywhere, with a 5.1 surround sound live performance studio as the centerpiece and a clean slate of modern equipment. Only a Minidisc player and the incidentals for live bands were kept from the basement.

WTMD now has a state-of-the-art facility, using audio-over-IP (AoIP) and structured wiring. Consoles, computers and satellite receivers are all networked using AoIP. The facility sample rate is 48kHz, rate converted to 44.1kHz at the output of an Optimod 8500 and then conveyed via an Intraplex NetXpress Multiplexer at an E-1 rate (2Mb/s) over single-mode fiber to the transmitter facility. The Intraplex, Harris Z12 HD+ transmission system and Orban were provided in a 2008 project with the knowledge that the facility might move.

Photo by Jack Dana

Photo by Jack Dana


Facilities include a performance studio with dedicated control room, two production rooms and an on-air studio A. The on-air studio has a dedicated secondary control room that can also be used for production and as a control room for shows on the Baltimore Channel, which is carried on HD2. The performance studio fixes one end of the 200-person SRO lobby, but can be closed off with a folding glass wall and acoustical drape. The remaining studios are arranged down one long hallway with a common glass wall looking out toward the Towson Circle.

Fully networked

All the operational areas are networked through a technical operations center (TOC) that sits between the performance studio and the other rooms. This TOC was built as an audio data center, complete with 45kVA UPS, secondary ac power source in each rack, computer room air conditioning and monitoring. The room has its own ground pulled to a sub-basement termination in a ground ring. The audio network uses the Axia LiveWire AoIP technology.

Each production room and the air studio have a 16-mic level in by 8-line level out patch panel to permit the production of multiple musical events. These patch panels feed PreSonus DigiMax 8 preamps, which then feed inputs of two Axia X-nodes. The X-node outputs feed the line level return jacks. In this manner, studios can be used as isolation booths, independent of the rest of the room. Each of the six rooms and the technical center has a Henry Engineering Multiport analog/AES interface panel as well. Any source, anywhere, anytime, including sources generated by the network, was a mantra in the design.

Except studio B, each room has an Axia Element 20-fader control surface and Power Station engine. There are CAT-6 patch panels, but there are no punch-blocks in the facility. From the engine, network cabling extends power and data to X-nodes in a studio as necessary. This facility has 48+ X-nodes, about half of which are in the TOC. Each studio is built as an island (except band patch panel nodes that are direct to TOC). The engine connects on a 1GB port to a Cisco 3750 managed switch. (Fiber is an option). Of course we have to build for redundancy and maintaining uptime, so each studio has analog and AES patch points between the engine and TOC. Each studio has a local PC equipped with the Axia single-channel driver. The studios have Denon CD players and flash recorders, Genelec monitors and two KVM workstations that allow sharing of computer assets including the Wide Orbit automation system. The Wide Orbit computers and NPR receivers connect to the network via Livewire.

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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.

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The performance studio and a few other spaces share an Audio Visual system including video projector and motorized screen, Crestron 5.1 surround sound with stereo mixdown to QSC K-series powered monitors under the control of a Lectronsonics DM series processor, Blu-Ray player, VGA/HDMI wall ports, PTZ HDMI cameras, signage and video streaming servers all to an Aurora 8x8 HDMI/HDBaseT Matrix. The outputs feed GM, conference room, lobby, reception and projector destinations. Video and song now playing are also routed to a massive ticker-style moving message sign that wraps around two sides of the studio building.

The technical operations center (TOC) sits between the performance studio and the other control rooms.

The technical operations center (TOC) sits between the performance studio and the other control rooms.


The facility has a master clock, however it is not GPS derived. Because the station carries network programming, it was felt better to receive and generate an NTP clock derived from the NPR/PRSS receiver. This clock is distributed over the networks to console, automation and wall clocks.

The studios, TOC and transmitter room share access to the building''s 480Vac/650kVA generator. The transmitter room also has an Emerson 45kVA UPS with maintenance bypass and Emerson computer room grade A/C.


What is Structured Wiring?

The term structured wiring, rather than the broadcast specific Studio Hub approach to such wiring, has been used for a reason. I am providing this detail because you may have to explain this, as did I, to third parties and we have to use their IT terms, not our broadcast terms. One has to separate the network from the node. Nodes are devices that connect to networks. Networks, and their cabling, should be agnostic to the attached devices and signals, unless there is a really good reason to do otherwise. Any competent low-voltage wiring firm can install structured wiring.

Why structured wiring? Because it works? Well, yes it does, and quite well, but that is not the reason. “But it costs more.” Not necessarily. Stepping out of the broadcast mindset, and speaking as a project manager, one has to look at the practical reality of getting things done under increasing layers of technology and regulations against tighter budgets and deadlines. You can very clearly define an scope of work, a bill of materials, a budget and sign-off criteria when you specify the number of runs of CAT-6 UTP terminated in modular ports per room. Try explaining that you need X different types of multipair, terminated in X different types of connections, and then find out you need something different, and try to purchase that difference. Anything other then CAT 5/6 UTP, or STP, or fiber, becomes a showstopper. Businesses make so much use of structured wiring now that it is the standard for wiring.


Equipment List

Allen & Heath GM24
Appo Blu-Ray
Aurora DMX88
Avocent AMX5100
Axia Element, Power Station, Radius, Pathfinder, Network Drivers, Smart Surface, nodes
Belden cable
Burk remote controls
BW Broadcast processor
CBT Systems on air/recording lights
Cisco and HP switches
Comrex Access, Access Portable
Crestron HDX5P
Day Sequerra modulation monitor
Dell and HP servers, PCs and monitors
Denon DNC640, DNF650R
Electro Rack Barracuda
Harris HD+
Henry Engineering Multiport, Matchbox
Inovonics 632
Intraplex NetAccess Multiplexer
Lectronsonics DM812
Lucid SSG192
Master Clock Systems MCR5000
Middle Atlantic Products KVM drawers
Neumann TLM102
OC White ProBoom
Ortronics and LCOM structured wiring products
Panasonic projection and camera devices
Presonus Digimax D8
Radio Systems Studio Hub+ headphone amps, integration products
Samsung TV monitors
Sony MDR 7506
Studio Technology Furniture
Studio Tools AES DA
Tieline Bridge-IT
Valcom powered ceiling speakers
WatchFire and Tightrope Media Digital Signage
Wohler, Genelec and QSC K-series monitors and speakers
Wide Orbit 3.5



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