In the previous two posts, we considered some questions that we need to ask and answer before selecting a PA. Once we have an idea of what we’re trying to accomplish, what our design criteria are and how we can implement that design, we still have a few more choices to make. I told you this wasn’t an easy process!
Powered or Unpowered?
A decade ago, an audio amplifier was big, heavy and required a lot of current to work well. Today, even powerful amplifiers can fit into small spaces and don’t weigh nearly as much. As a result, more manufacturers are opting to include them in their speaker systems. There are some significant benefits to this approach. First, the amplifiers can be exactly matched to the speakers. Since the amp is in the box, cable runs are incredibly short, which means nearly 100% of the amp’s power is deliver to the speaker, not turned into heat in the cable. Crossover points between drivers can be optimally set, and often DSP included in the box, which makes for a far more predictable system.
The downside is that if an amp goes on a speaker that is 50 feet in the air, someone has to go up and change it. You also have to supply power to your powered speakers, which means double the number of cables running to each box. And the inclusion of amps also means the powered speakers will be slightly heavier than their unpowered brethren. This is not typically a problem, but it has to be considered.
Which is better? Like all things in audio, that depends. Often times, powered speakers are an excellent choice as many of the tuning decisions have been optimized at the factory, which means it should take less time getting them sounding great in the field. On the other hand, if your installer wants to do something rather custom to accommodate a specific situation, sometimes the added control of separate components is better. The availability of power and space for amps also factor into the decision.
Thankfully, there are excellent choices in both powered and unpowered varieties and it’s not uncommon to see the same speaker available in both powered and unpowered versions.
Line Array or Point Source?
Line arrays—multiple identical boxes hung close together in a vertical line—are all the rage right now. And to be sure, they solve a lot of problems in certain situations. They typically boast good pattern control, are very efficient and are easy to rig; characteristics that make them excellent choices for large venues. Nearly every large tour is using line arrays right now for those (and other) reasons. They are not the right choice for every venue, however.
Smaller rooms (under 500) will often be better served with a more traditional point source box. In small rooms, it’s difficult to hang a long enough array to achieve good pattern control, and they get very expensive very quickly when compared to a point source system. Don’t fall into the trap of thinking that since line arrays are “new technology” they are inherently better. There has been a lot of development going on in both types, and modern point source systems can be incredibly effective when designed well.
A relatively new type of system is emerging as a great problem solver for certain rooms; the digitally steerable array. Using a larger number of small drivers and a bunch of digital signal processing (DSP), these systems can be life-savers for problematic rooms. A digitally steerable array can vary it’s coverage both vertically and horizontally to keep sound going where the people are and away from where they are not. Because they typically use a bunch of small drivers, their footprint is small making them ideal for very traditional rooms where aesthetics are a big deal.
Get a Listen
If it’s at all possible, you want to listen to the speakers before buying. Ideally, you would be able to hear them in your space. This may not always be possible, or it may not be free. You may have to spend some money to rent the speakers, or at least pay for a demo. If you’re looking at a smaller system, the local rep may have some boxes he can bring by. You may not get a whole system, but you’ll get a good idea of whether these speakers will work for you or not. Having a set of tracks of your band using virtual soundcheck is a terrific way to audition the speakers. If you can’t arrange for the speakers in your room, try to visit a venue that has them. This is less ideal, but will give you a good idea of what they sound like.
Which type of speaker to buy comes down not to selecting the “best” speaker, but rather the best speaker system for the room. Thankfully, the science of speaker design has evolved to a point where we can accurately predict performance before hanging boxes. Being able to try out different models inside the computer is a great aid to developing a great sounding system. What speakers you select will vary depending on the room, style of service and what environment you are trying to create. There are plenty of options out there, so with proper research and a good design, the end result will be a system that meets the needs for your church.