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Portable Sound Systems for Band/Orchestra Applications

Mike Lawson • • April 4, 2016

Wenger Speaker CartSimple, Affordable Solutions for Live Sound: In the old days, the idea of a sound system for school band/orchestra applications was pretty simple. There typically wasn’t anything at all, unless you included a 100-foot microphone connected to the gymnasium/ stadium/cafetorium’s (typically awful) sound system used for announcements or someone singing the “Star Spangled Banner.”

Flash forward to 2016 and we live in a different world, where the musical content often contains electronic keyboards, MIDI tracks, electronic drums and more — including vocals and miked solo players — who should not suffer the degradation of being routed through a horns-on-poles audio system in a stadium. These days, players, bandleaders and audiences deserve — and expect — better.
Today’s sound systems are light years ahead of where they were a decade ago. High-efficiency woofers and tweeters, built-in digital signal processing to optimize speaker performance and high-output/ lightweight Class-D amplifiers offer power levels previously unknown in compact speakers. And in addition to more punch, these features also make P.A. systems easier to use and more affordable.

The Simplest Possible Example

No system — no matter how wonderful sounding — does any good if it’s difficult or cumbersome to operate. A few years ago, my sister and her friend, who often do sing-along events at Girl Scout events, asked if I could provide her with a P.A. to handle an audience of 1,200 girls. She essentially knows nothing about sound systems and they would have to set the audio rig by themselves.

I could have sent them out with the latest digital mixer, a rack of amplifiers, speakers and all the required cabling, but there was no time available for teaching them about such a rig and what they really needed was to be clearly heard while singing from a stage.

The solution was simple enough. I put together a package with a couple Shure SM58 mics, two 50-foot mic cables and two Mackie SRM450 speakers. The SRM450’s have onboard amps and like most affordable P.A. speakers these days, can accept a line-level input from a mixer or connect directly to a microphone.

With one mic plugged into the speaker on the left of the stage and the other on the right, they adjusted the mic level on each to the proper volume and were set up in less than three minutes. The performance came off perfectly and many of those in attendance said it was the best sound they had ever heard at that event.

I’m not trying to imply this approach is ideal for every situation — far from it — but the point here is to illustrate that a simple, effective, easy-to-use system can be assembled without a lot of fuss or aggravation.

Going Even Simpler

The previous example is pretty basic, but sometimes, you need an even simpler solution, especially in grab-and-go field situations where AC electrical power may or may not be available. With that in mind, Anchor Audio (anchoraudio.com) offers the MegaVox Pro line of public address systems.

Housed in a compact 14 x 13 x 8.5-inch, 15-pound package, the Anchor Audio MegaVox Pro (anchoraudio.com) is essentially a megaphone on steroids, with two mic inputs, a line input and an onboard 20-watt amplifier driving its high-efficiency re-entrant horn speaker at up to 119 decibels (measured at 1 meter) for reaching out to 1,000 feet. Intended for vocal applications, the MegaVox Pro is lightweight and easy to carry, with battery and AC powering. Standard features include a 35mm speaker pole socket, onboard Bluetooth audio reception and an external speaker output for driving an optional companion speaker for wider coverage. Other options include packages with wireless mics. System pricing begins at $840/street.

The SW615A Half-Mile Hailer from AmpliVox (ampli.com) is an AC/DC-powerable system equipped with a megaphone-style horn, 60-watt amplifier with a line input and up to three microphone inputs. The SW615A includes a wireless mic (a second wireless mic is optional). It’s also offered as the SW635, an expanded system with the SW615A Half-Mile Hailer, a remote S1264 horn extension speaker, a 40-foot cable, two speaker stand tripods and a reinforced nylon case with carry handle and wheels. The basic SW615A has a street price of $579.

Stepping Up

Call it what you want — speaker on a stick, or whatever — but music- quality portable systems, with their fast, easy setups have become a bread and butter mainstay of the live sound industry and, combined with a subwoofer or two, can offer impressive performance in smaller venues, while holding their own in field applications.

These powered, one-piece systems are all about flexibility. All feature a bottom-mount, 35mm pole socket that is compatible with standard tripod speaker stands. And nearly all powered subwoofers include a pole mount socket, making setups a breeze, with the sub enclosure providing a stable base for the upper speaker cabinet. These can also be stacked, or tilted back for use as stage monitors, thus expanding their functionality. Many models also include fly points for installation applications, although suspending overhead speakers requires specialized structural load knowledge and certified rigging that — for both safety and liability issues — should only be performed by an experienced professional.

Ideal for medium-sized venue use, these speakers have a modular approach that lets your use what you need. You can start with a pair of speakers, add the subwoofers as needed (or not at all) and then employ them as required. These can be fed from an external mixer and most also have outputs for daisy chaining to a second speaker or to provide a separate feed to feed a house system or stadium P.A. During rehearsals, these make an ideal keyboard amp for a digital piano, or a direct input from vocal mic — hard-wired or with a wireless unit.

The following is a selection of popular models — all with onboard biampli­cation and 12- inch woofers. For many users, this format makes the most sense. The 12-inch woofer packs enough low-frequency reproduction to make these truly full-range speakers — even without an optional subwoofer. These are light enough in weight to make setups fairly easy — hoisting a 75- or 80-pound speaker atop a six-foot tripod stand is no fun. And all the companies listed here make variants in larger or smaller packages (typically with 10- or 15-inch woofers), so if you want to go upstream or downstream, check the manufacturer website for more info.

Power to the Speakers!

The usual industry term for a transducer with onboard ampli­cation is a “powered speaker,” but without a source of electrical power the term “loudspeaker” is pretty meaningless. All sound systems for large-scale sound reinforcement require an AC power connection. Indoors, locating a couple outlets is not usually a problem, but it’s an entirely different matter when you’re performing on a football ­field or in a grandstand.

This can come in the forms of an inverter or generator system. An inverter takes a DC power source (typically one or more car batteries) and outputs a 120 VAC feed. Inverters can range from the simple plug-into-auto-cigarette-lighter units to much more powerful systems. The advantage of an inverter is that they are silent and don’t require operating a gas or diesel engine generator. The downside of inverters is that they are limited in power output (total watts or amperes), require remembering to charge the batteries before the gig and once the batteries are discharged, the show is over.

Generators, on the other hand, can continue producing electricity as long as you can keep the fuel supplied, although some models can be fairly noisy and using internal combustion engines, will emit exhaust. Another side of using generators or inverters regards the cleanliness of the power. This is not a major factor with power tools or lights, but “dirty” power can create havoc with any system using computer-based circuits or digital signal processing, which includes most sound systems and electronic instruments, as well as computers.

Portable power systems with pure sine wave (rather than modi- ed sine wave) inverters offer clean, glitch-free power and are recommended for sound and music applications.

Another issue — whether with inverters or generators — is the power capacity of the unit, which is usually given in watts. To calculate your load requirements, simply add up the total number of watts your gear draws Note: This is NOT the same as the amplifier’s output power rating. For example, thanks to its efficient Class-D amplifiers, a JBL EON612 draws 430 watts maximum, so you could safely run two of those (860 watt draw) with a 1,200 watt supply, which would allow a decent margin of additional power reserve, as well as enough capacity left over to run a small digital mixer and some wireless mic receivers. However, if you’re planning to use powered monitors speakers and subwoofers, the power capacity would have to be increased accordingly.

Inverters are available on an a la carte basis, creating an opportunity for a DIY project of combining the inverter unit itself and some automotive or marine batteries. Creating such a unit is not overly complex, but building an easy-to-use, portable rig with a safe convenient means of charging the system and some kind of wheeled cart to haul the heavy batteries complicated matter somewhat.

As an alternative to a generator, a commercially available, self-contained inverter package such as the Xantrex XPower Powerpack 1500 (xantrex.com; street price around $465) is an option to consider. This system has a battery pack that stores electricity, inverter that convert 12 volts of DC power to 120-volt AC with two standard outlets, as well as a DC power panel that can feed 12 volt DC gear. An integrated wheeled cart makes transport simple. Continuous output is rated at 1,350 watts.

On the generator side, choices are many, but recommended for music and audio applications is the Yamaha EF2000ISV2 (yamahamotorsports.com; $1,099/MSRP), the smallest is its popular EF series of quiet operating models. Other units in the line range up to the 6,300- watt EF6300ISDE. The EF2000ISV2 has a rated AC output of 1,600 watts. Features include a quiet, 4-stroke 79cc engine and a dry weight of 44 pounds. The 1.1-gallon gas tank will power the unit up to 10.5 hours and the noise level (depending on load) is 51.5 to 61 dBA.

Getting It There

Contrary to that old saying, getting there is NOT half the fun, especially when it comes to hauling heavy sound and band gear to the gig. Fortunately, numerous alternatives exist in the way of specialized carts for transporting instruments, speakers, percussion/ keyboard setups, uniforms, music and all else such as those from Wenger (wengercorp.com), who offers a complete line. Among these is the company’s OnBoard Speaker Cart, which not only offers secure transport and a tilt back that can angle the sound toward the audience.

Of course, anything that can save the collective backs of sound techs is OK in my book and the Jarvis Speaker Mover (jarvisonline.com) has a large 41 x 20-inch tray and can adjust speaker tilt from vertical to -30 degrees. Easy and fast: That works for me!

George Petersen is the editor of FRONT of HOUSE magazine.

 

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