TECH TALKA Primer on Mixers and Amplifiers
By Jim Boratko In previous issues, I've discussed a speaker system and different microphones. This edition will discuss mixers and amplifiers. First, what is the difference between a mixer and an amplifier? A mixer is the component that you will plug your microphones and other components into. A mixer contains a number of dials, knobs, and sliders that will allow you to refine the sound your microphone provides. It does not amplify the sound - it only refines it. While it may have many inputs for mics, instruments, and other devices, it usually only has two outputs - a left channel and a right channel. These channels will either go directly to powered speakers if that is what you have, or to a separate amplifier. Since the mixer does not make the sound louder, you may need a separate amplifier to increase the signal's power to make the sound audible from your speakers. An amplifier will have only one or two inputs and one or two outputs. NOTE: If your speakers are powered speakers, they include an amplifier within them, so you do not need an amplifier. You'll only need an amplifier if your speakers are passive. You can easily tell the difference between the two different types of speakers. If you have to plug your speakers into a power source for them to operate, they are powered speakers. Passive speakers do not require you to plug them into an electrical outlet. Several factors must be considered when selecting one (or both) of these components of your church's audio system. Here are a few questions you should answer before striking out to replace or purchase your system:
Let's go through each of these points for some clarity and elaboration. We've already discussed how to tell if your speakers are powered or passive above, so we won't go into that further. Again, if they are powered speakers, you only need a mixer, not an amplifier. The number of devices/mics/instruments you intend to plug into the system will dictate how big of a mixer you may need. Mixers generally come in sizes of 8, 12, or 24 channels. A single device or microphone will require a corresponding channel. Connecting more than one microphone or device to a single channel is not usually recommended, as you won't have control of the individual devices. You'll only be able to control them in tandem together. Also, consider the types of inputs you will have. Microphones usually have a three-pin connector called an XLR input, while instruments, CD players, and other electric gadgets will have a ¼" phone plug connector. Even though a mixer may advertise eight channels, it may only have 4 XLR compatible sockets to plug in up to 4 mics. The other four channels are reserved for the other devices. So, if you intend to plug in more than four mics, you'll probably need a 12-channel mixer instead of an 8-channel mixer. The area you wish to cover with sound will be a determining factor. The larger the area you want to cover, the bigger the speakers and the more power you require. Conversely, a smaller speaker system and lower powered amp would be adequate if your space is smaller. The more people you have in a particular space, the more sound they will soak up. A person's body and clothes will absorb the sound you are sending out, meaning you'll need a higher-powered system if the room holds many people. Also, consider whether the space has a lot of sound-absorbing items in the room. Drapes, carpets, seat cushions, choir robes, and other softer textured items will soak up the sound and prevent reverberation in the room, which may dictate a higher-powered system. Finally, consider the ambient noise in the space. Naturally, for church services, where the spoken word and music are the focus of the congregation's attention, there is usually not much conflicting noise competing for attention. However, if you expect to send out a message when there are a lot of people conversing simultaneously, you will need to ramp up the volume. That's a lot to consider, I know. I am fortunate that my church has several different systems that we use for varying purposes and situations, so here is a breakdown of three different systems that we own and how we use them for your consideration:
Our stand-alone podium is a small sound system with a mic built into the podium. The amplifier and speaker unit are in the lower portion of the podium. It does have the capability to add another microphone, and there is a built-in CD player as well. The fidelity is acceptable for the spoken word, but it is lacking for music. We use this unit for our chapel (about 30'x50'), which can hold about 90 people. Our PA System is a very robust system with two large passive speakers on poles. I put together a small power amplifier/mixer combination, which we have in a rolling enclosed cabinet. The amplifier is 250 amps and can drive these speakers very well. The power mixer has four mic channels and four line channels. We've used this system indoors and outdoors in large spaces for public rallies and music performances with much competing traffic noise. It is our most powerful system.
Our Meeting House System is our most versatile, state-of-the-art system. This system utilizes nine different powered speakers located throughout the meeting house. The speakers are directional, meaning they focus their output on specific areas of the congregation. Because of that, no one is more than 50' away from a speaker, so you don't have to turn up the volume excessively. The room that they service is about 50'x250'. We have four wireless headset microphones, two wireless handheld microphones, two focused microphones covering the organ and the choir, two mics in the room to capture congregational singing, and two boom mics to capture music performances at the front of the space. We can also add 12 microphones through a box attached to the system (often referred to as a "snake" by audio professionals). All of these inputs are handled through a wireless iPad interface and can be managed from any point in the room.
Next time will talk about all those knobs, dials, and sliders on the mixer and what they do. ■
Jim will share some of his tips in a recurring column concerning the use of technology in worship. If you have any questions or want to suggest a future topic for him to address, please get in touch with Jim at jim.boratko@whfirstchurch.org. | A Message from The Rev. Karen Georgia A. Thompson Our First “Worship, Music & Ministry” Issue Singing Welcome to Outsiders within the Congregation Happy Upcoming 350th Birthday, Isaac Watts! Christians in Nigeria: A Follow-up Cliff’s Notes: A Jazz Opera Comes Alive TECH TALK: A Primer on Mixers and Amplifiers MUSIC DOWNLOAD CROSSES
"Upright cross with outwardly widening ends. It is often seen in relics from the late antique and early medieval Byzantine Empire (until c. 800) and was adopted by other Christian cultures of the time, such as the Franks and Goths." — Wikipedia
LOOKING BACK – 30 YRS.  The first 22 years of Worship, Music & Ministry in print. |
Jim Boratko has been an organist and music director for nearly 40 years. He retired from his corporate IT job in 2015 and now devotes himself full-time to his passion for music. His technical IT and network support background merged with his musical experience as we navigated from in-person experiences to virtual rehearsals, concerts, and worship services.
Worship, Music & Ministry is a publication of the United Church of Christ Musicians Association, Inc. and is issued three times a year. The journal is distributed to members of UCCMA as a benefit of membership. All correspondence concerning membership in UCCMA, changes of address and other inquiries should be addressed to the United Church of Christ Musicians Association, P.O. Box 370631, West Hartford, CT 06137. Information about the United Church of Christ Musicians Association is available at www.uccma.org. Copyright © 2024 by the United Church of Christ Musicians Association, Inc. |
|
