CAN YOUR WORD BE HEARD?
By: M. Eugene Lysinger
In churches, these three are found: microphones, amplifier, and loudspeaker. But the greatest of these is loudspeakers.
Yes, the loudspeaker is key to the entire audio chain. Reason: As the speaker sounds, so sounds the complete package.
Implication: Good stewardship and good sense suggest a good understanding of loudspeakers to help in their selection.
LEARNING THE LINGO
Every discipline has its lingo, and if you can speak the language, you can contribute to a better decision.
*Speaker system: A group of drivers.
*Driver: The vibrating part of a loudspeaker that reproduces the sound. Sometimes a system utilizes drivers of one type; sometimes types are combined.
*Direct radiator: A type of driver, including cones, domes, ribbons, and flat panels.
*Horn: A horn-shaped driver that can come in many different configurations and sizes to accomplish particular functions.
*Woofer: A low-frequency driver.
*Array (or cluster): A woofer-horn combination repeated several times around an arc.
MAKING SOUND DECISIONS
Unsatisfactory speaker selection sometimes results from using nontechnical criteria, such as:
*How a speaker sounds in the store or with a home hi-fi.
*A pleasing price.
*Brand recognition alone.
Better: Decisions to buy and install loudspeakers can follow a logical process that includes a hierarchy of decisions. Answering these questions in order prepares a church to consider specific recommendations.
What are the acoustic conditions of the room in which the loudspeakers will be placed? Note: A particular brand or type of speaker that works in one sanctuary won’t necessarily work in another.
Mistakes: Acoustical consultants sometimes must recommend taking down expensive installations that haven’t performed up to expectations. Then churches must spend yet more money to attain the results they want.
Reason: The original system was purchased with an inadequate
understanding of the church’s acoustics.
What kinds of sounds will the loudspeakers primarily broadcast? The crucial distinction here is between speech and music. Which will be the primary use? Problem: Speech and music don’t coexist naturally in the same speaker system, so how the speech-music question is answered determines, to a great extent, what kind of speakers to use.
Here are some specifics:
*Speech. We perceive and process speech in the left hemisphere of the brain. Key: Think of the process of decoding amplified speech as mathematical. For good intelligibility, the fewer separate impulses the
brain has to sort out to reassemble a word, the better.
What to look for: The best speech loudspeaker system will have few elements, and the elements will send sound directly to listeners’ ears. Reason: This setup produces the fewest impulses, allowing sound to arrive at the ear with a high ratio of direct sound as compared to reflections and reverberation (a good direct-to-reflected ratio). Also: The speakers will be aimed down at the listeners to take advantage of their sound absorption.
*Music. The right-hand side of the brain perceives and processes music, and, oddly enough, the more diffuse the sound and the more reverberation (up to a reasonable limit) the better. Reason: Some acoustic characteristics that make music pleasant often make speech hard to understand.
Worth considering: It is possible to reinforce speech intelligibly in highly reverberant acoustics. Music and speech can coexist reasonably with individually appropriate audio hardware. Result: It demands hard choices, however, and sometimes dual systems.
What are the visual realities? Often churches must reconcile a loudspeaker’s primary function with its appearance. Key: Don’t purchase a speaker primarily for its appearance.
Worth considering: You may have more visual latitude than you think. Method: Answer the earlier questions thoroughly, and then consider appearance among speakers appropriate for your situation.
What are the amplification system’s specifications? Key: Can the amplifier provide the necessary power and control to allow the loudspeakers to do their job without distortion or damage to themselves?
Caution: An amplifier with too little power can ruin loudspeakers. Related problems: Insufficient amplifier power or poor equalization can also degrade sound quality and intelligibility. Solution: Make sure the amplifier is teamed properly with the speakers you choose.
Is the proposed budget realistic? Key: The church’s needs must feed into the budgetary process. Implication: Those who determine the money available to purchase the system must be educated about sound problems and solutions before financial constraints are set.
GETTING THE RIGHT HELP
With the battle between the conflicting needs of amplified speech and music, not to mention the intricacies of architecture, acoustics, and electronics, how can churches – even informed churches – ensure wise loudspeaker decisions?
Advice: Find a consultant. Reason: The field is too technical and the potential costs of a mistake are too great. Look for an adviser who:
*Knows the field of acoustics thoroughly and has experience working in it.
*Understands and can communicate how loudspeakers work mechanically and electrically.
*Can determine how various types and configurations of loudspeakers will interact in your church. Note: There is no such thing as a loudspeaker whose sound quality, accuracy, volume, and intelligibility can be assured without calculating its interaction with a specific environment.
*Has observed the performance of many kinds of loudspeakers in a variety of situations. Reason: Such experience provides information from which to draw recommendations.
Suggestion: Contact the National Council of Acoustical Consultants (P.O. Box 359, Springfield, NJ 07081- 1409; 201/379-1100) for a listing of qualified consultants.
Whether you are upgrading a system (meaning: “Let’s get these problems finally solved!”) or laying out a new system, you can avoid problems through advance planning.
New construction. Invite the following people to a building committee meeting before you start working with an architect:
*An electrical engineer/designer.
*A heating, ventilation, and air-conditioning designer.
*An acoustical designer and/or engineer.
Cost: Expect to pay two to three hundred dollars each for a long evening with your committee. Benefit: You can save many times that amount as these people help you measure not only the cost of architectural features but also their acoustical consequences. Each specialty must work with the others to help facilitate your loudspeaker decisions.
System upgrades. If you are upgrading a sound system, get the acoustical advice first. The result will be much happier for everyone.
Tip: Potential donors often appreciate being included in a meeting with the acoustical adviser. It informs their decision and underscores how crucial and significant their donation can be.
There are no dumb questions about loudspeakers. There are, however, uninformed decisions. An ounce of investigation can be worth many pounds of replacement.
LOUDSPEAKER MANUFACTURERS: WHERE TO LOOK
This list, while not exhaustive, gives you some of the leading loudspeaker manufacturers to contact for information and materials.
P.O. Box 26105
Oklahoma City, OK 73126
APOGEE SOUND, INC.
1150 Industrial Ave.
Petaluma, CA 94952
14270 NW Science Park Drive
Portland, OR 97229
Framingham, MA 01701-9168
9130 Glenoaks Blvd.
Sun Valley, CA 91352
8500 Balboa Blvd.
Northridge, CA 91329
737 Canal Street, Building 23B
Stamford, CT 06902
TANNOY NORTH AMERICA, INC.
300 Gage Ave. Unit 1
Kitchener, ON, Canada, N2M 2C8
(The above material appeared in a January/February 1991 issue of Your
Christian Information Network