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Loudspeakers Carry the Message
With so many houses of worship turning to other components to enhance the worship experience, such as amplified music, drama, and video presentations, loudspeakers must not only clearly support the message of the spoken word, but also deliver full-range music reproduction. Regardless of whether your service is spoken word alone or a full multimedia event, selecting speakers for your house of worship is perhaps the most critical choice you'll need to make. This guide explains some of the concepts of loudspeaker selection and placement. If you have questions regarding loudspeakers or any aspect of sound systems, call us at 1-800-222-4700.
Speaker Placement
| Often the best speaker placement is centered overhead, a few feet in front of the pulpit. |
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Regardless of how much you spend for a system, or how good it looks, without correct speaker placement, even a high-quality system will sound mediocre at best. The dimensions of your sanctuary play an essential role in not only speaker placement, but also speaker selection.
In a typical mono system, speakers mounted to the left and right of the platform can introduce dead spots and poor intelligibility, which results in listener fatigue. Speakers mounted in the four corners of a sanctuary will alleviate the problems of a left-right system to some degree. However, if you are sitting near the rear of the sanctuary, your eyes will tell you that the sound source is in front of you, while your ears tell you it's behind you - which can be a tad disconcerting.
So, where should speakers go? In many cases, the ideal position is overhead, usually a few feet in front of the pulpit, centered left-to-right in the room. This method ensures even sound coverage from front to back, and proper localization for the original sound source. The exact location of the speakers is determined by a number of factors including size and shape of the room, location of the platform and seating, and sound pressure levels required. Since our ears are not very good at localizing sound on the vertical plane, when combined with your visual perspective, a speaker cluster that is actually 25 or 35 feet above your head will still have the illusion of sounding as though it's coming from the pulpit.
Choosing The Correct Speakers
Before you can make an effective choice of speaker type and configuration for your room, you must determine how much coverage is needed. How wide and how deep is your room? Will one speaker suffice, or will you need two, three, or more? For deep rooms with a ceiling that's lower than 18 feet, some form of a distributed system may be needed. A distributed system comprises front speakers and extra speakers to fill in the middle and rear seating areas. The fill speakers are often called delay speakers, since they need to be time-delayed. The reason for time-delay is due to the fact the sound travels quite a bit slower than electricity. For those sitting closer to the rear, they'll hear the sound from the back speakers before the front ones, causing a disconcerting echo effect. The time delay compensates for the speed and distance the sound will travel so that it appears to emanate from all places at once. Some rooms need only a couple of delayed fill speakers to cover the most rear seating sections. Other rooms must employ many rows of speakers, with each set for a different delay time.
Two-way, Three-way
Professional speakers designed for permanent installations come in many flavors: two-way, three-way, component systems, line array, and systems supported with subwoofers. A two-way system provides a low-frequency driver ("woofer") and a high-frequency driver ("tweeter"). Often a subwoofer is added for extended bass response. A three-way system adds a separate speaker or horn to handle midrange frequencies.
What is a Crossover?
A two-way loudspeaker system comprises a low-frequency woofer with a high-frequency horn. Sound reinforcement two-way loudspeaker enclosures have a crossover as part of the design. A crossover, which is a filtering device, separates the audio frequency spectrum and directs portions of the spectrum to either the woofer or the horn. All of the frequencies below the crossover point go to the woofer, and all of the frequencies above this crossover point are directed to the high-frequency horn. A three-way system uses multiple crossovers to divide the frequency spectrum into three sections, sending low, midrange, and high frequencies to a separate device.
 Line Array
When a worship application really requires a concert-style level of audio support, line arrays can be ideal. Line arrays provide tighter vertical pattern control and typically more consistent sound pressure levels from the front to the back of the room. But line arrays can cause problems of rear reflections, and the design requires greater vertical height for mounting. They are typically not good for shallow rooms and can be more expensive. Still, an increasing number of churches, both large and small, are choosing line array loudspeaker systems with supporting subwoofers both for regular worship and for staged events of all kinds. An example of such a system is Peavey's SSE LA line array and companion SSE 210 subwoofer.
It's important not to overlook the inherent design complexities of line arrays. You could end up with less-than-complete coverage and severe reflection problems. Call your Sweetwater Sales Engineer first if you're considering a line array system.
 Do I Need a Subwoofer?
| A subwoofer can often actually reduce overall volume in the sanctuary |
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For spoken word alone, a subwoofer is not a necessity. If you're using line arrays, under-balcony, balcony, and delay speakers, a subwoofer is needed for full-range reproduction. If you're combining music with spoken word, a subwoofer is most certainly a necessity if you want a powerful and inspiring musical performance. Often a well-implemented subwoofer can actually reduce overall volume by balancing the frequency response of the entire sound system. The JBL JRX118S is an unpowered subwoofer with an 18" driver.
 Benefits of Self-powered Speakers
Self-powering eliminates the need for external amplifiers, signal processing, equipment racks and heavy-gauge wiring - all of which adds significantly to the cost of conventional systems and to the labor required to install them. Rack space is often at a premium in church installations, and loudspeakers with built-in power amps eliminate the need for amplifier rack space. The Mackie SA1232z is an example of a three-way powered speaker.
 Flown, Floor-based or Stand-mounted?
In fixed installations, the ideal choice is to fly the speakers. However, stand mounting is an acceptable option. Active speakers such as the Mackie SRM450 have built-in receptacles so they can be pole-mounted. The JBL EON 1500 weighs only 38 lbs. and has both a stand-mount receiver and hanging points for ceiling or wall mounting.
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