Recently, U.S. states that lifted coronavirus restrictions reversed course, as cases surged and hospital beds started filling up across the South and West. So, with the pandemic grinding on, and with entertainment and worship venues closed for inside assembly in many states, let’s take a break from my series on immersive live-sound and look at how venues can-do better-quality sound outside.
While speakers-on-a-stick (small loudspeakers on a tripod) are ubiquitous (as shown in Fig. 1), there are quite a few upgrade options available above such entry-level loudspeaker solutions. I applaud JBL’s development of its 1995 EON series, and how these developed and ushered lightweight plastic enclosure loudspeakers into the market (with many imitators to follow), but there is a lot of room for improvement both in terms of output and pattern control. Speakers-on-a-stick (typically with a 10”, 12” or dual-8” woofers) have modest output and little pattern control except at the highest frequencies — sending most of their LF energy into space, and as such they are better used for indoor applications (or outdoors as distributed or delayed satellites).
While we’re on the subject of speakers-on-a-stick, several of the newer loudspeakers look like a stick-on-a-baby sub (a woofer, really), as shown in Fig. 2. Bose was innovative in coming up with the miniature column loudspeaker, and many other brands have followed in their footsteps over the past two decades. This class of tiny columns can project a narrow vertical sound beam rather far, so they can be useful. But the first generation of these tiny columns have poor pattern control (too narrow vertically as the frequency goes up), and they are inadequate for outdoor applications of any significant size or SPL. Note that some of the latest-gen mini-columns optimize spacing and the angle of drivers, or incorporate digital beam steering to offer more consistent or venue optimized directionality (a.k.a., directivity/polars).
Such misuses of technology reminds me of how people doing the sound for the Beatles concert at Shea Stadium in 1965 used several of the large column speakers as the main loudspeakers. Even for just the infield, they were completely inadequate. (The installed paging system was used for the stadium seating.) I doubt they were ever intended for large outdoor venues or expected to be effective over the noise of such a loud crowd.
A Brief History of P.A.
I feel that it would help to review P.A. loudspeaker history. The first-generation P.A. speakers were all/fully horn loaded, due to the high efficiency required to work with the very low-power tube amps available over half a century ago. When I was first learning about P.A. systems, the Altec A7 Voice of the Theatre systems (smaller horn-loaded 2-way) loudspeakers in Fig. 3 were still commonly used for relatively high-quality large indoor and outdoor applications. About that same time, line-arrays were just big column loudspeakers (w/out horns), popularized by the Shure’s 1968 Vocal Masters and others, as famously used by Frank Sinatra and countless others. Although P.A. subwoofers did not yet exist, these vintage loudspeakers did a decent job of projecting vocals for very large festivals; much more suitably than a basic/modern speaker-on-a-stick does now. Note that some of today’s latest generation large-format columns are very capable.
While the American P.A. speaker manufacturers later turned to more compact direct-radiating designs with more emphasis on lower-frequency performance, some of the leading European loudspeaker manufacturers have continued to develop fully horn-loaded loudspeakers solutions for concert/P.A. applications.
The next time you are looking for new speakers, avoid the temptation of asking your local music store or online salesperson what the coolest/smallest new loudspeaker is. If you want the right loudspeaker for the job, ask a loudspeaker engineer or a design consultant (like myself); or at least seek out an applications engineer at your favorite speaker manufacturer to talk about an appropriate selection that’s optimum for your application and type of venue.
In terms of a single box solution, consider stepping up to a larger loudspeaker with at least two 12-inch or — better yet — two 15-inch woofers, much like a classic cinema system from two or three decades ago (or a large fully horn-loaded design). Such large loudspeakers normally have higher output and can do a better job of focusing the sound on the listeners. However, although once quite common, few are still available today.
There are modern updates to the classic horn-loaded loudspeakers currently available, in what I would call the arena class or one-box array loudspeakers. These large loudspeakers commonly include a large bass horn or four 12” to 15” front-loaded woofers. (One of my end-fire one-box array designs has five woofers. For more on this, see the August 2019 issue of FRONT of HOUSE.)
Of course, few smaller venues have the facilities or budget to fly a line array outside, but there are still compact line array and sub solutions that can be stacked on the platform, when a more modern speaker is desired, with further projection and higher output than a classic one-box loudspeaker, or when large systems w/horn-loaded woofers are not readily available.
While your typical speakers-on-a-stick may do a decent job of music reinforcement in a small room, they are not an ideal choice for P.A. applications (meaning voice amplification) and/or light acoustic music reinforcement outdoors. And of course, if a rock band format is involved, considerably greater power/SPL and frequency range (multiple subs) will be needed.
Thanks to several industry leaders, one of the first important things I learned about sound system design was that the speakers are the weakest link in an audio system chain. In large venue and outdoor applications, it is even more critical that loudspeakers are chosen and set up wisely. With all due respect to the powerful new digital consoles and the cool wiz-bang software plug-ins, they still can’t mix music without a human, and a live sound system still won’t sound very good unless the loudspeakers are chosen appropriately for and well optimized in your venue.
Next month, we’ll look at outdoor sound suggestions from several loudspeaker manufacturers.
David K. Kennedy operates David Kennedy Associates, consulting on the design of architectural acoustics and live-sound systems, along with contract applications engineering and market research for loudspeaker manufacturers. He has designed hundreds of auditorium sound systems. Visit his website at immersive-pa.com.
Related article by David Kennedy:
On a Budget? Sourcing the Best Loudspeaker for Outdoor Worship
On the subject of outdoor sound for worship, I spoke to Byron Mathe, the technical director at Shadow Mountain Community Church, a high-tech mega-church in East San Diego. I was so impressed with his planning and cost-effective solution to sourcing high-quality loudspeakers and electronics for their outdoor events, that I asked him to share some of his sound-advice with our readers.
“After several weeks of recording our services without a live audience and streaming over the Internet, our pastor was eager to have our congregation safely meet together again through in-person services outside,” Mathe says. “The pastor gave us six days notice before we had our first service and we did not know how long we were going to be able to meet, so for the first few weeks we hired a production company to provide everything we needed. The church services were successful and when we knew that we’d be outside for the foreseeable future, we decided it would be best to use our own equipment and purchase whatever equipment we needed to save on rentals.”
Mathe took a logical approach to the issue. “I like to run the church’s production department like a rental company, with a stock of gear that we use, to do the various events that we support. I purchase used equipment when it is available, at great prices from auctions, then restore it as needed so it’s ready when we need it. We would never be able to purchase all of the equipment we needed if we had to purchase it brand new. With this stockpile of gear, we had the majority of what we needed for this outdoor venue and I was able to supplement what we didn’t own with some more used and new gear. We used a local scaffolding company to build structures on either side of the stage to hold the P.A. and video screens. And we have a 40’x40’ self-climbing truss structure to hold a shade cloth and our lighting.”
If there isn’t enough budget for a quality new speaker purchase, and a compact/quick fix isn’t needed, like Mathe, I would rather find and update the drivers in a premium large-format used loudspeaker that has the optimum sound coverage and output level for the space, venue and program usage.
For a small fee, loudspeakers can be tested for condition, and if needed, most drivers can be reconed with original brand parts, or replaced by a budget driver. For a little more cost, most drivers can be replaced with new, higher-powered drivers, making them even better than new. There should be plenty of idle inventory at low prices, and loudspeaker experts available now, in most major markets. If you need help evaluating your best loudspeaker options, drop me a line at david@HDsound.US.
—David Kennedy
