New Sound Systems: Powered or Unpowered?

by Vince Lepore
in Sound Sanctuary
At Valley Bible Fellowship in Las Vegas, three powered VUE Audiotechnik hs-28 subs below the stage complement flown hangs of VUE al-4 and al-4SB elements.
At Valley Bible Fellowship in Las Vegas, three powered VUE Audiotechnik hs-28 subs below the stage complement flown hangs of VUE al-4 and al-4SB elements.

Powered speaker systems have evolved considerably over the past 20 years. The popularity of powered speakers has exploded, the price has come down substantially and the performance has improved. I’ve met a lot of audio engineers and techs that prefer powered speakers by default just because of the convenience, and don’t really stop to think about the long-term implications of powered vs. unpowered systems. The realities of the powered vs. unpowered debate are complex, and one type of system is not necessarily better than the other. As with most things related to audio, your individual situation will dictate which type of system you choose.

 ‡‡         Pros and Cons

Convenience: Powered speakers really are a great invention and an incredible convenience. Who doesn’t love to throw up a couple of JBL Eons or QSK K series boxes for a quick, small gig? For the small stuff, there really is no substitute for their convenience and simplicity. However, when considering a more substantial system, whether it is some new monitor wedges or a main PA for a new building, there are many factors to consider besides just the conveniences of powered speakers.

Closed Ecosystem: One of my favorite aspects of powered speaker systems is their closed ecosystem. I’m sure there will be many people who strongly disagree with me on this, which is fine, to each their own. However, I firmly believe that the signal processing, amplification and loudspeakers should all be designed to work together in harmony. That harmony should not be adjusted or disrupted by the end user. The idea of system owners purchasing a speaker system and then designing amplifier racks and DSP themselves makes little sense to me, and such a system is less and less common these days. A speaker whose processing and amplification is inaccessible means that many variables can be removed from the system, making it more predictable, as well as being easier to troubleshoot and tune. The flip side of the coin is that unpowered systems provide a lot more flexibility in how the speakers are powered and processed. Ultimately it comes down to just how much control you want over the powering and processing of the system.

Power Distribution: One of the biggest differences between powered and unpowered systems in a church is electrical power distribution. Unpowered speaker systems generally require a machine room to house amplifiers and other system electronics. Therefore, most of the electrical power required for the system can be installed in the machine room, and speaker cable pulled from the machine room out to the loudspeakers. In the case of a powered system where system electronics are housed inside of the speaker boxes, electrical distribution, possibly totaling hundreds of amps worth of circuits, needs to be pulled closer to the loudspeaker arrays. If you’re trying to re-use existing electrical, it most likely won’t be in the ceiling above your new powered loudspeaker array.

Footprint: If your church is anything like mine, you have challenges with storage and floor space in your facilities. I have yet to meet a church technician that complains about having too much storage space. Amplifier racks and system electronics take up valuable real estate. A powered system transfers those electronics from the floor to the ceiling. Sure, it will save you space on the ground and in your racks, but it will demand more of your structure if you are flying your PA. Powered speakers are considerably heavier on average. This shouldn’t be a deal breaker for most rooms, but it is a consideration worth noting.

Service and Repair: Sound system electronics are generally reliable, but years ago I had an amplifier melt down, starting a small fire in our amp rack. A few years later, we had a loudspeaker processor fail entirely, taking out the house right side of our PA. In the case of the failed processor, we patched around it to get the system up and running before Sunday worship. That was a relatively easy fix because the electronics were on the ground and easily accessible. Consider for a moment what would happen if that failure were to happen inside of a speaker cabinet that was part of a flown array. It would be much more difficult to service, especially on Sunday morning. While failures like this are relatively rare, they do highlight one benefit of having the system’s electronics on the ground.

Tuning and Processing: In an array of powered loudspeakers, each box contains its own amplification, independent of all other array elements. This opens the possibility of having granular signal processing (gain, EQ, delay) control over each cabinet in an array. On the other hand, most unpowered loudspeaker arrays contain paralleling between boxes, meaning that any signal processing applied to one box in a parallel chain affects the other boxes as well. While per-box signal processing might not be necessary or practical for most rooms, I have seen it come in handy on some systems, and if you can do it, why not?

‡‡         And, Last but Not Least…

The Sound: Of course, we are talking about sound systems after all, aren’t we? The sound is what matters the most, and there are amazing sounding powered and unpowered systems available at similar price points. One type of system is not inherently better than the other. Before making a purchasing decision, listen to as many systems as you can, preferably in your own worship space. Ask your A/V integrator for demos or shootouts so you can listen to systems side by side. Finally, choose the system that sounds best in your room and fits the criteria you have based on your unique facility.

Vince Lepore is the technical director at St. Luke’s United Methodist Church in Orlando and teaches live production at Full Sail University.

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