CUT THE CORD - EMusician

CUT THE CORD

With a laptop music system and a portable P.A. package, it's possible to play almost any type of venue. Unfortunately, that means you're still tethered
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With a laptop music system and a portable P.A. package, it's possible to play almost any type of venue. Unfortunately, that means you're still tethered to a wall outlet because P.A. gear requires AC power, and a laptop's battery drains astonishingly fast when running a host of USB-powered peripherals (such as a control keyboard or an audio interface). However, you can lose your dependency on traditional wall outlets by investing in your own portable power supply. With the right setup, you will truly be able to play anywhere, from a city street corner to a wilderness meadow, without worrying about where your power will come from. Portable power supplies for running everything from small laptop setups to large P.A. systems are available (to rent or buy) in price ranges that will fit most budgets.

COMPACT SYSTEMS

Contrary to what you might think, an earthshaking P.A. system is not always appropriate. For intimate woodland gatherings or a cozy chill tent, a small pair of active studio monitors (such as M-Audio's StudioPro 4s) can get the job done. And you can run a laptop, a USB-powered control keyboard, a USB- or FireWire-powered audio card (such as MOTU's Traveler) and petite active monitors off a well-designed battery pack for a few hours. Of course, operation time will vary depending on the size of the battery and the power draw of your equipment (more on this later).

A readily available battery pack that can run a laptop for about six hours is the Xantrex XPower Powerpack 1500. Although it weighs in at a hefty 60 pounds, it's designed like a rolling luggage bag, with built-in wheels and an easily attached pull handle. Maximum continuous power is rated at 1,500W for 10 minutes with a peak surge capacity of 3,000W. It has two 115V AC outlets (check your speakers to make sure that they will perform okay with 115V) and can be recharged from a standard wall outlet (15 hours) or from your car's cigarette lighter (eight hours) with the included DC charging cable. You can even employ a 100W solar panel to augment the battery's charge, reportedly letting you run a laptop for nearly 13 hours. (You can find this as well as solar-panel backup power kits online at www.costco.com.)

POWER TO BLAST

If you want to run a full-blown P.A. system with all the amenities, you will need a gas-powered generator. These are small engines that run off the same gasoline that you put in your car. A popular model is the Honda EU2000i, a 3.5-horsepower, single-cylinder, overhead-cam, air-cooled engine that weighs in at 46 pounds. It features two 120V AC outlets, with a 1,600W rated output (2,000W maximum). The fuel tank is a touch more than a gallon, and on a full tank, the engine will run for approximately four hours at the rated load and 15 hours at a quarter of the rated load. The retail price is $1,100, but you can generally rent the EU2000i for about $60 a day. If you don't need that much power — or you need more — Honda also sells models below and above the EU2000i: the EU1000iA2 (26 pounds) and the EU3000is (134 pounds), respectively. (If you need even more power, look into renting a diesel-powered “movie generator,” such as Aggreko's SuperHush Movie Generator, starting at about $350 a day.)

As you might expect, a gas-powered engine can be noisy, but the Honda generators are designed for superquiet operation. Nevertheless, because of noise and safety concerns, operating a gas-powered generator is illegal in some areas. If you plan to play in a public place and want to avoid getting a ticket, be sure to check with the city before firing up your generator. On private land, always make sure that running a gas generator is okay with the property owner. Also, never refuel while the engine is running or hot; gasoline is combustible, and the engine's hot surfaces could cause a spontaneous ignition. The Honda generators don't have wheels, so save your back and invest in a hand truck.

ADDING UP THE WATTS

The key to selecting a power supply that will work for you is to make sure that the unit's output in watts is approximately twice the total wattage of all your gear. To find the total number of watts required to power your gear, add up all the watts for each piece of equipment. (If this information is not noted on each unit itself, you can usually find it in its technical documents.) Then, multiply that figure by two to find the minimum watts that a power supply should have to run your setup. It's important to overshoot your wattage requirements because most generators aren't as efficient in practice as their specifications would have you believe, and there are always unexpected circumstances that can affect your power needs (such as extra gear and scorching weather).

Furthermore, gas-powered generators and most battery packs do not provide audiophile-quality power, known as pure sine-wave power. Instead, the power from most standard portable power units is a jagged sine wave, which is inadequate for making error-free digital recordings. Such discrepancies in power can also cause damage to sensitive equipment, especially gear with RAM-based memory (like samplers and effects units). The solution is to employ an uninterruptible power supply (UPS) with a built-in regulator between the power source and your equipment. The regulator will work to maintain steady power and safeguard your gear, and the battery backup will keep your systems running in the event of a momentary blackout (I've seen a UPS save a show in just this situation.) If pure sine-wave power isn't a concern, Belkin makes the Regulator Pro Gold Series ($60). If you want to capture a pristine digital recording, check out Belkin's Regulator Pro 1400VA with pure sine-wave power ($600).