The EM Poll

The Show Must Go On

Jan 11, 2008 5:01 PM, By Pat Kirtley

           

RULE #5 DON'T LET INADEQUATE AC LEAVE YOU POWERLESS

Stage equipment is totally dependent on a source of constant, reliable AC power. Unless you play exclusively in one venue, every new show offers the possibility of AC power problems, including overloads, grounding problems, and audio interference.

You can help prevent overloaded circuits by knowing in advance how much power your equipment draws. Here's an easy way to do it. Make a list of all the electronic gear that your band uses (see the sidebar “Calculate Your Power Needs”), including lights if you have them. Then look at the back panel of each unit, and write down its AC wattage rating. (Don't get these power consumption ratings confused with power output — for a given piece of equipment, the two are rarely the same.) Next, convert the wattage ratings to amperage ratings, since that's the way AC circuits in buildings are rated. (On some gear, especially the pro-audio variety, the power consumption rating is already expressed in amperes.) The conversion takes a little math, but it's easy. Divide watts by 120 (in the United States, the standard line voltage is 120 V) to get the rating in amperes. Now, add up all the amperage ratings to get the total AC load requirement for your band. This is a conservative figure. The total (peak) current isn't reached unless you are at maximum volume level with the lighting system at full brilliance; the average load is considerably less.

With your power numbers in hand, you can now take a more intelligent approach to setting up in any venue. Many wall-outlet circuits are fed by a 20-amp circuit breaker. If you exceed 20 amps of current at the outlet, even for a short time, the breaker will trip. A good strategy to use to avoid overloads is to find outlets served by separate circuits and divide the equipment load between them. The most obvious split is to connect audio and lighting gear to separate circuits.

Try to find “clean” circuits that have no load on them (for example, refrigeration units or miscellaneous lighting) other than yours. Having a dedicated AC access also helps avoid audio interference problems caused by things such as compressor motors starting and stopping.

Another important AC supply factor is the cabling you use to get from the wall socket to your equipment. Since there are so many individual power cords for all of the units on the stage, it is necessary to combine them into just a few lines going to the power outlets. The best way to do that is to use heavy-duty power outlet boxes, which can be either purchased from an electrical distributor or made up by an electrician. Avoid department store extension cords, even if they are the rugged-looking “outdoor service” variety. Most of them have cable conductors too small to deliver sufficient current to band equipment, especially at lengths approaching 50 feet, the maximum length typically required at venues. When it comes to AC power distribution, get the good stuff and you'll never look back.

RULE #6 MAKE CONTINGENCY PLANS

Even after you've learned to be cool and logical in tracking down sound-system problems and you've taken preventive measures, you can still be slammed by something much worse than a bad cable or flaky connection. When major problems, such as the failure of a critical piece of gear, occur just before show time, solving the problem becomes a matter of survival. The secret is to work out, in advance, specific actions for specific failures. It's a creative game you can play during off hours. Start by playing “what if?” with your current roster of equipment to determine ways to go on with the show.

It's a good idea to develop quick-response contingency plans for all the possible failures that might occur. Do you know how to switch the P.A. over from a triamp to a biamp configuration if a power amp should fail? If your instrument amp dies, do you have a preamp that you can use to plug directly in to the P.A.? Do you know where all the fuses are in your equipment and how to get to them during a show? Do you remember where you keep the spare fuses? Do you know how to properly mic an acoustic guitar in case its internal pickup system goes out during the show?

These are things that allow you to keep the show rolling even though failures occur. Just think, “What can go wrong?” and develop creative ways to deal with each possible disaster scenario. Besides coming up with ideas for work-arounds, this is also a good time to write down a list of possible spare items to carry with you (see the sidebar “A Musician's Survival Kit”). Fuses, batteries, special cables, vacuum tubes, adapters, and field-replaceable speaker drivers are possible life-saving items, and you are unlikely to find them nearby at 8 p.m. on the evening of the gig.

With gear that contains programmable processors, including keyboards, MIDI controllers, lighting controllers, and some effects processors, losing a patch or program can mean the loss of a critical sound element or effect capability. Although most units don't lose user programming when disconnected, it's fairly easy for someone to overwrite your settings accidentally. Find a way to reestablish your important programs. Many units have a System Exclusive (SysEx) function that allows you to save the programs on a notebook computer. Finding out how to back up the unit is worth it for the peace of mind you gain.

RULE #7 NO MATTER WHAT — THE SHOW MUST GO ON!

I recently attended a concert of a group that I like. Everything was going great until just before the last number, when all power to the stage failed — lights, sound, everything. Instead of saying “Oh well, good night everyone,” the band moved to the edge of the stage and played the last tune acoustically. In the dimly lit auditorium, the audience of 1,200 held its breath as the group performed its most memorable song of the evening. The crowd response was deafening, and no one there will ever forget how effectively those guys handled the worst failure you could imagine. You got the impression that they'd gone through that before and had a plan.

Performing live can be a totally thrilling experience, if the technology works the way it is supposed to. There will also be moments when things break down and refuse to function. By developing the winning combination of coolheaded common sense, preparedness, prevention, and a disaster response plan, you'll have the satisfaction of knowing that no matter what comes your way, the show will go on!