Audiomixers: in houses of worship
Mar 1, 1998 12:00 PM
An audio mixer must perform many different tasks in houses of worship, some conventional and some not. To understand the needs of the modern worship system, we must first identify the three primary jobs that a mixing console is called upon to perform: live sound/voice reproduction, fold-back/remote monitoring and recording.
The spoken word The most important aspect in regard to systems designed for use in houses of worship is the degree to which the system reproduces the spoken word faithfully. Spoken words in prayer, regardless of denomination, are essential to religious gatherings, so intelligibility is vital. Although microphone selection is important, all audio-mixing consoles must provide a clean and clear low-impedance pre-amp stage with the ability to trim the input signal level. Also necessary is some means of sensing overloading input signals at the individual input, either via an LED peak light or VU-type averaging meter. The reason for this arrangement is simple-without the ability to set the proper input levels and sense peaks, there is a good chance that spoken words can sound distorted.
In addition, a good EQ section is essential. Although a parametric equalizer section is desirable, it is not necessary if the proper mics are selected for the application. A shelving EQ section providing fixed frequency boost and cut options with some midrange control is fine for most applications. The ability to reduce the low frequencies gently is important, as transferred low-frequency vibrations on the lectern or pulpit can be a nuisance. Because voice-range frequencies are in the midrange centered around 2 kHz, it is a simple matter to roll-off the low frequencies below 80 Hz to 100 Hz without affecting the intelligibility; in fact, rolling them off will enhance the vocal range. The shuffling of books or other items on the lectern or pulpit surface and accidental bumping into the lectern can cause these low-frequency vibrations.
The vocalists Almost as important as the spoken word are the choir, soloists and other vocalists. The traditional use of zone miking techniques and reverberation effects to enhance the sound of a soloist or choir are still widely practiced, but many applications require multiple inputs from handheld mics. The handheld miking technique is used when groups sing together, and they can be either wireless or wired mics. Using so many different miking techniques reinforces the need for a good input section on the mixer because these microphones are often pushed to their limits. The engineer must maintain control of level, distortion and feedback in multiple miking situations. Because the types of vocal performance can change with each service, it is crucial for the mixer to have adequate EQ. Often, an outboard de-esser or compressor is necessary to thwart problems with vocalists, and outboard reverb or other effect devices help embellish the voice. The audio mixer should allow insertion of an outboard device on the channel itself or have at least one effect send and return for the entire mix.
Musical instruments Traditionally, organs used to be the main source of music, and it was common for organs to have their own stand-alone reinforcement systems. Although organs are still widely used, a wide range of musical combinations can appear in many contemporary houses of worship-from small electric combos to full orchestras. As the number of instrumentalists increases, more attention must be given to the needs of managing this part of the service. Number of available input channels at the console should be the first consideration. It is not uncommon for a service to resemble a conventional concert when it comes to mixing with many inputs from instruments and mics. Because there will be a greater need for monitor mixes, a console with multiple outputs will also be desirable. The number of instrumentalists and vocalists will determine the number of inputs needed, but keep in mind that it never hurts to have too many input channels. Because it will be necessary at times to have guest instrumentalists accompany a vocalist, it is a good idea for the mixer to have extra channels set aside.
Miking such instruments as acoustic guitars, cellos, violins and a large assortment of other traditional and folk instruments on the fly is common, and these instruments frequently have internal pickups that are not low impedance. It is never wise to run a high impedance line more than 10 feet (3 m) because of interference. For situations where high-impedance sends are used, it is prudent to insert a direct box as close as possible to the high-impedance signal source. The direct box allows conversion from high to low impedance for better transmission of the signal into the console.
Playing back recordings Most systems need to have the ability to play back recorded material. In the age of multimedia, houses of worship are finding new and creative ways to impact the people attending a service, and recorded media is employed on an increasingly frequent basis. The mixing console selected will need to have the facility to accept inputs from compact disc and tape players, many of which are high-impedance devices with RCA-type consumer connectors. It is helpful if the console has matching RCA high-impedance inputs with a gain stage to adjust volume of the material going to the mix outputs. In a pinch, regular input channels can be used if they are switchable between mic and line, but on a smaller mixer, these are often in short supply. It is generally a better idea to have a console with an accessory input designed for a playback device.
Monitor systems Many different ways of monitoring program material must be accomplished in houses of worship. Foldback monitoring is necessary for the musicians to hear cues, and it is sometimes crucial for the podium area to have foldback capabilities, especially in large facilities. The most important aspects for the musicians are intelligibility of the voice, pitch, tempo and blend. Because of space limitations, the monitoring system should often be compact, which can dramatically affect sound quality. Outboard compressors and EQs can increase the quality of these mixes when the monitor size is compromised.
There are also ancillary rooms that are used for overflow during holiday periods and special events. These spaces, along with dressing rooms, waiting rooms, office areas, hallways, and convertible areas of the facility, require program monitors. Any of these may require separate volume levels, so multiple sends and sub-mixing capabilities are essential on the mixing console.
Because every application differs, laying out needs for different zones on a floor plan of the facility is helpful. Once the number of separate level mixes for the environments is determined, there are many ways to find sends from the mixing console. Even smaller mixers can provide a variety of output possibilities. If one adds up the number of subgroups, stereo and/or mono outputs, pre/post monitor and effect sends, monitor busses and tape or playback sends, there are usually enough adjustable output sends to cover the many needs.
In many cases, it will be necessary to control numerous individually tailored mixes. For example, the pianist will have different monitor mix needs than the vocalist. An overflow room or hallway distributed ceiling loudspeaker system requires a full mix of all channels, which is often an entirely different mix than the one sent to the main feed for the sanctuary. It is important to determine just how many monitor mixes will be necessary and how much flexibility of control will be needed before a proper mixer can be chosen. In larger facilities, it may be necessary to have a completely separate monitor console solely for handling the monitoring load. In other applications a small console with outboard mixer or on-board matrix mix will give enough flexibility to accomplish the task.
Recording Recording services is growing in importance, as many people wish to experience again special family events, sermons, and musical performances, or to distribute tapes. Many houses of worship are installing sophisticated video and audio production systems, allowing full production of program material for internal use and broadcast distribution. In many installations, all that is needed is a regular two-channel recording device. Having a sub-mix output channel on the console is instrumental for making these recordings because it allows the mix to be faithfully reproduced as it is mixed. There are times, however, that for effect one may wish to mix in the sound of the congregation or even create a separate individual mix totally independent and unaffected by the main system mix. This is usually done in one of two ways: either with tie-lines set up allowing a dual path to a second console or via a monitor/effects mix or strategically placed mics tied directly into the recording device. Using the monitor or effects mix bus allows each channel to have a volume level independent of the master output routed to the main loudspeakers. Most mixers have a mix that is switchable before or after the EQ section of the console so the signal can go to the recorder with or without the EQ that has been set up for the main sound reinforcement system. If the acoustics are particularly good in the facility, it is common to record via well placed recording mics routed directly to the recording device or routed to the console and accessed via an alternate sub output. Whatever the choice, the key is to have a console that allows the flexibility to accomplish all of the mixing needs that the congregation may encounter.
Choosing the right console for the house of worship requires careful attention to current and future needs. It is certainly easier to outgrow a console than it is to have too many features.
Acceptable Use Policy blog comments powered by Disqus
