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electronic MUSICIAN

Battling Medusa

By KAREN STACKPOLE | June 1, 2001

If you're like many small-studio owners, the mere thought of venturing behind your gear racks fills you with dread. The tangled mass of cables back there can be so awful and overwhelming that just a glimpse of it will paralyze you. This is the modern version of Medusa, the gorgon from Greek mythology whose hair was a mess of writhing snakes. She was so hideous that anyone who looked at her turned to stone instantly.

Medusa was slain by Perseus, who avoided that stony fate by only looking at her reflection in his polished shield. Now you, too, can tame the dreaded cable gorgon with a little forethought. In any recording or mixing studio, a well-planned and obsessively neat wiring scheme saves you from headaches, frustration, evasive sonic gremlins, and postinstallation expenses. Why suffer the consequences of shoddy workmanship when you can do it right the first time? With careful planning and execution, you can easily avoid the most common studio-wiring mistakes.

I called upon three studio experts with extensive wiring experience to provide a broad perspective on the professional approach to studio wiring. Ann Dentel, formerly of David Carroll Electronics, spent a lot of time under the floors at Skywalker Sound in Marin County, California, and designed the wiring for numerous studio facilities around the Bay Area. Dentel operates Anzrad Cables, also in the Bay Area, and teaches the art of wiring at Ex'pression Center for New Media in Emeryville, California. I also contacted sound designer and EM contributing editor Larry Oppenheimer of Toys in the Attic, a music and audio services company. He has done wiring work at Fantasy Studios, Russian Hill, LucasArts, and Pro Media, all in the Bay Area, in addition to many project-studio installations. Lastly, I spoke with technical wizard Lawrence Fellows-Mannion of Rance Electronics, an Oakland, California — based, full-service recording-studio maintenance and installation business.

THE DRAWING BOARD

You've heard the adage “If you fail to plan, then plan to fail.” Those are fine words to live by when you take on the task of wiring your studio. But before you dive in headfirst, take stock of your situation and do some serious in-depth analysis. What equipment do you have? How will you use it? What is the studio's layout? Now is the time to decide what setup best suits your working style, ergonomically and in terms of efficiency. Figure out what gear goes into which racks. The pros organize their studios by area, designating locations for specific stations, such as the mixing console, the patch rack, the synth rack, and the computer (see Fig. 1).

Once you draw a diagram of where everything will go, the real work can begin. Larry the O suggests that you make an equipment database, documenting every connection in detail. As you separate things by station, generate reports of the inputs and outputs of every piece of gear in a rack, to sort out your cable and connector needs. At the least, draw up an organized, detailed list of each station's gear and connections (see Fig. 2). From there, you can figure out what to bring to a patch bay for easy access.

Use the I/O report to make a wire list based on your studio layout. Determine the cables you need and measure the distances those cables must run. Add an extra three to four feet to that for slack to “dress in” your racks, and leave an adequate service loop (several feet of slack) that will give you access to the back of your gear later on. Compile a complete supply list that includes cables, patch bays, connectors, and materials for conduits or troughs, according to your master plan. Don't forget to include a cable-management system, incorporating permanent and temporary cable ties, a labeling kit, and other incidentals.

Formulate a budget for high-quality cables, connectors, and patch bays if you want your wiring efforts to last. If you need to economize, don't compromise the grade of components you buy; rather, decide what can be left out of the patch bay, such as mic lines or connections to gear you use for only one purpose. By hardwiring those items, you save on the extra cable required to bring things to a patch bay.

Plan for expansion so that you don't wire yourself into a corner. Fellows-Mannion recommends starting with 20 to 30 percent more cables than you need for a new installation, because you will grow into it; the extra cables will ease the addition of new equipment.

Before you start wiring, thoroughly research grounding, digital routing, and interfacing balanced and unbalanced analog connections. For grounding advice, see “Square One: Power to the People” in the October 1997 issue. For digital-audio etiquette, read “The Route Less Traveled” in the December 2000 issue. Those are important topics that go beyond the scope of this article.

There are rules for interfacing balanced and unbalanced gear, but the most important one is to be consistent. Decide on sensible grounding and interfacing schemes and be consistent as you wire your studio. Stick to that modus operandi religiously to avoid problems later.

CABLES AND SNAKES

Your wiring job should ideally be a one-time affair. At the onset, avoid setting yourself up for failed connections. A sound investment in good cable is a great place to start. You will hear a difference in fidelity, and your cable will last. Because of its performance and affordability, Larry the O prefers cable by Proco and Whirlwind for reliable, everyday needs. High-end cables from companies such as Mogami, Canare, Gotham, and Monster Cable are excellent choices, but from an economic standpoint, it might not make sense to wire your entire studio with the high-end stuff. However, consider using it for some critical connections, such as mix outputs and mic lines. (For more about cable types, see “Good Connections” in the January 2001 issue.)

Fellows-Mannion has this advice about selecting cable for a pro audio-wiring installation: “If you need to get as many lines as possible into a narrow trough or space, use foil-shield cable such as Canare, Belden, or Gepco small gauge, because each pair is smaller. Spiral-wrap cable from Canare, Mogami, or Gotham is best when extra flexibility is needed. Braided-shield cable is by far the best choice for areas where it will be flexed or stepped on a lot. That type of shielding is the most robust of the three cable types.”

In addition, Fellows-Mannion recommends using shielded twisted-pair cable whether the gear is balanced or unbalanced. The shield protects against electric fields, and the wire's twisted configuration inside the cable makes it less susceptible to magnetic fields. “Balanced line connections provide some measure of noise rejection,” Fellows-Mannion says. “When you have a mile of cable crisscrossing through your studio, you want as much protection as you can get.”

Utilize snake cabling as much as possible; it's neater and easier to lay. Larry the O recommends the David Carroll Electronics modular standard of running everything in 8-channel chunks. That makes it easier to change or add things.

“On the other hand, there are advantages to breaking it out,” Dentel says. “That way you have a separate cable for each piece of gear, which is easier to dress into the rack and easier to troubleshoot.” She admits that separate cables are harder to deal with on the patch bay end because you wind up with a prodigious amount of 4-pair or 2-pair cable coming into the back of your rack, which is more challenging to keep neat.

CABLE LENGTHS

“It's best to make your cables prior to your installation and test each cable before you lay it in and connect it,” Larry the O says. “If you don't, you'll have to check every one of your connections after installation. That's less than ideal because it's unlikely that you'll have 100 percent success the first time through.” However, Dentel advises that you wait to terminate cables that will be pulled through a conduit or small holes until they have been drawn through and are securely in place.

If you have a movable rack that will be shuffled back and forth, leave a service loop so that you can move the rack as needed. It's also a good idea to leave a service loop at the patch bay so you can work on it (make new connections, fix broken ones, and so forth) if needed. Don't make your cables too short. Remember that tying cables to a structure, such as a rack or table leg, takes extra length. It is better to err on the side of making your cables too long than making them barely long enough.

After you figure out your cable lengths, it's time to acquire the materials. You will need plastic cable ties long enough to handle the girth of the cable bundles you plan to tether, and removable and reusable cable ties, which are often made of Velcro. (You can purchase both types of cable ties inexpensively at most major hardware stores, and better-quality Velcro cable ties are available at electronics stores.) Velcro strips work fine for temporary snake bundling.

DOCK OF THE BAY

The heart of your studio's infrastructure is the patch bay, which lets you bring connections from many gear pieces to one easy-access panel for routing and patching purposes. Consumer-level, 2-conductor, ¼-inch phone-plug patch bays may seem affordable and convenient, but the professionals advise steering clear of them. “You get what you pay for,” Larry the O says. “Remember, there are a lot of connections, and you're constantly plugging and unplugging, so the quality of your contacts is important. The cheap ones aren't really worth it.”

Fellows-Mannion doesn't recommend consumer bays with ¼-inch jacks on both sides and built-in switching mechanisms that control top-to-bottom normaling. Those switches tend to develop reliability problems because of their construction.

Even if most of your gear is unbalanced, always default to 3-conductor patch bays. They not only provide good protection against interference but also enable studio expansion. A robust yet flexible infrastructure is the best approach. If you want a jack-to-jack bay with jacks on the front and back, a long-frame bay (which uses longer plugs than the standard ¼-inch variety) with 48 TRS jacks might be the way to go.

If you need to fit many connections into a smaller space, tiny telephone (TT) bays have 96 jacks on the front; the back connections are solder tails, punchdown blocks, or connectors such as Elcos or Edacs. “Soldered connections are the best, but that's a fairly permanent installation,” says Fellows-Mannion. Remember to plan for expansion and flexibility. Consider which option suits your studio's cabling needs.

Based on how you work and what gear you routinely use, it's generally a good idea to create “normal” connections between pieces of gear at the patch bay, to make your job more convenient. In this scheme, one device's output, typically in the bay's top row, is connected to the input of another device directly beneath it by default, so you don't need to patch in a cable for normal operation. If you wish to change the setup, the connections are centralized in the patch bay; simply reroute a signal, with a patch cord, to the destination of your choice.

You can make the connections half normal or full normal (see Fig. 3). With a half-normal setup, the normal signal path is broken when you plug in to one of the connections, usually the input. With a full normal, the path is broken when you plug in to either connection. Use full-normaling for mic inputs to the board and mic lines from mic panels or snakes, and half-normaling for processors that you might reroute as necessary.

DOCUMENT IT

To make sense of the mess when you need to troubleshoot or add new connections, labeling your cables is crucial. Take your list of cables and connections and develop a code to identify each of them. Be as detailed as possible, indicating the station, function, and line number of each. Larry the O suggests getting a labeler that can print very small type; you can find one at office-supply stores for about $60. He also recommends buying a few extra rolls of labeling tape, because you're going to need them.

“Place labels close to the connector but not too close, in case you need to open the connector,” he says. Dentel suggests, as a standard, placing labels about two inches down from each connector. You might have to turn some labels lengthwise on the cable but be consistent. Develop a system and stick to it. Label both ends of the cable and the connectors as well. Keep detailed documentation for reference.

LAYING IT ALL OUT

Now that you're ready to lay it all out, which cables can run together and which should be kept separate? First and foremost, keep the AC power cords away from the audio cables so you won't induce noise into the audio. If your audio and AC cables must intersect, cross them at a 90-degree angle. Larry the O prefers to keep digital- and analog-audio cables separate because analog audio is susceptible to picking up noise. He recommends keeping the AC, digital-audio, and analog-audio runs separate, but he says that you can often get away with running digital audio with AC at the rack.

Most AC inputs are generally on one side of the equipment rack, so run the AC cords up the side of the rack closest to the most AC inputs. “Unshielded transformers, wall warts, and lump-in-the-line power supplies tend to be big sources of radiated electromagnetic fields,” Fellows-Mannion says. “It's a good idea to keep your audio cables away from those. You should also keep your phone lines [telephone, modem, and DSL] away from your audio cables, because ring voltages in phone lines can reach 90V.”

However, DC lines from wall warts can run alongside audio cables if necessary, along with other low-voltage power-supply lines such as a DC line running from an outboard power supply to a piece of equipment. “If you're running separate ground wires from your gear to ‘star ground’ [a grounding scheme], bundle those with your audio to keep the loop area between the audio and ground lines small. That helps reduce the possibility of hums and buzzes,” Fellows-Mannion says. “Those ground wires should run with your audio and not your AC.”

TIE IT UP, TIE IT DOWN

At this point, it's time to bundle the cables you'll run from station to station. Use permanent ties for cables that will be less likely to require access, such as tape machine sends and returns, tie lines (nonassigned line-level cables that allow equipment in different rooms to be connected as necessary), and mic cables. If you think you will have to change something from time to time or you have gear that you move around a lot, use temporary ties to fasten those cables to the main bundle. That will ensure that you can reach the cables when needed.

In preparation, take the cables that go from one station to another, such as from the mixing console to the patch bay, and lay them out on the floor. Larry the O recommends you start from the end that will go to the equipment (as opposed to the end that goes to the patch bay) and line up the connectors so they're even. Bundle the cables with a temporary tie about four inches from the connectors. About eight inches down from that (or whatever length you need for your breakout), put on the first permanent cable tie. Then work your way down to the other end, bundling the cables with permanent ties every 6 to 12 inches. Be consistent with the spacing and finish off the bundle with a temporary tie about four inches from the connectors at the other end. Dentel says not to use cable ties if you're laying cable in a trough or pulling it through a conduit.

Now you can go to the equipment end and plug everything in. Run the bundle neatly to the patch bay, placing it out of foot traffic's way. At each rack, run the analog-audio cables up one side and the AC cables up the other. To secure the cable bundles, attach cable mounts (gadgets with slots to accommodate cable ties) to the rack's sides (see Fig. 4). This ensures that you don't have a zillion cables running amok across the back of your rack. You need to break cables out from your bundle at various levels to connect them to the appropriate patch point or piece of gear.

Larry the O recommends that when you break out your cables, you use a strain-relief bar, which could be as simple as a sturdy wooden dowel running horizontally across the back of your rack. As you loom the cables out to designated connection points, tie the slack to the bar so that the cables' weight doesn't pull on the connectors and jacks.

Above all, be neat and organized. If you get sloppy with your cables, the back of your rack will look like Medusa on a bad hair day — going around the back to troubleshoot an intermittent connection might leave you stony and immobile, as though you laid eyes on the gorgon herself.

OUT OF SIGHT

In a professional installation, most of the cabling is hidden, either in troughs underneath the floor or in cable raceways or trays along walls or above drop ceilings (see Fig. 5). If you designed convenient cable passageways into your room, you can lay your cables neatly out of the way.

There are special considerations if you use a conduit, which is commonly made of metal electrical piping. “If you need to put cabling inside of the conduit, it's going to be pulled rather than laid,” says Fellows-Mannion. “Manufacturers make special cables for this, with a thicker and stronger jacket designed not to stretch when it is pulled. This is where you have to use single cables and fish tape to pull them together through the conduit.” Fish tape is like a long measuring tape that you can use to “fish” the cable through the conduit.

If you don't have a conduit, a raised floor with a cable trough, or a raceway above your ceiling, your cables have to snake across the floor. If it's impossible to keep the cables out of foot traffic, use a cable bridge so that they aren't trampled. “I recommend getting [adequately sized] PVC tubing,” says Larry the O. “Saw it in half lengthwise, and place it over the top of the cables. You get a very solid, weight-bearing plastic protector.” The main point is that the more out of the way, out of sight, and protected your cables are, the better off you are (see Fig. 6).

EXPANDING WORLD

Each wiring installation has its own unique requirements, and you can take many routes with your studio, but several philosophies remain consistent, regardless of the situation. Planning is key. It's important that you don't underestimate factors such as cable lengths, conduit or trough size, and your studio's growth potential. Consistency and neatness are paramount. You must implement a uniform and clear labeling system. Documentation is essential if you don't want to have a nervous breakdown when it's time to troubleshoot.

Do your research about grounding and interfacing balanced and unbalanced gear, as well as analog and digital connections. Adopt a grounding scheme and an interfacing system and be consistent with them. Leave yourself some room to grow. You have carte blanche to be obsessive-compulsive when it comes to wiring your studio. Embrace your inner control freak. Whatever you do, don't let Medusa do you in.


Karen Stackpole is director of studio maintenance at Ex'pression Center for New Media in Emeryville, California. Many thanks to Ann Dentel, Larry the O, and Lawrence Fellows-Mannion for their experiential wiring wisdom.

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