Audiomixers: in houses of worship
Mar 1, 1998 12:00 PM
An audio mixer must perform many different tasks in houses of worship, someconventional and some not. To understand the needs of the modern worshipsystem, we must first identify the three primary jobs that a mixing consoleis called upon to perform: live sound/voice reproduction, fold-back/remotemonitoring and recording.
The spoken wordThe most important aspect in regard to systems designed for use in housesof worship is the degree to which the system reproduces the spoken wordfaithfully. Spoken words in prayer, regardless of denomination, areessential to religious gatherings, so intelligibility is vital. Althoughmicrophone selection is important, all audio-mixing consoles must provide aclean and clear low-impedance pre-amp stage with the ability to trim theinput signal level. Also necessary is some means of sensing overloadinginput signals at the individual input, either via an LED peak light orVU-type averaging meter. The reason for this arrangement is simple-withoutthe ability to set the proper input levels and sense peaks, there is a goodchance that spoken words can sound distorted.
In addition, a good EQ section is essential. Although a parametricequalizer section is desirable, it is not necessary if the proper mics areselected for the application. A shelving EQ section providing fixedfrequency boost and cut options with some midrange control is fine for mostapplications. The ability to reduce the low frequencies gently isimportant, as transferred low-frequency vibrations on the lectern or pulpitcan be a nuisance. Because voice-range frequencies are in the midrangecentered around 2 kHz, it is a simple matter to roll-off the lowfrequencies below 80 Hz to 100 Hz without affecting the intelligibility; infact, rolling them off will enhance the vocal range. The shuffling of booksor other items on the lectern or pulpit surface and accidental bumping intothe lectern can cause these low-frequency vibrations.
The vocalistsAlmost as important as the spoken word are the choir, soloists and othervocalists. The traditional use of zone miking techniques and reverberationeffects to enhance the sound of a soloist or choir are still widelypracticed, but many applications require multiple inputs from handheldmics. The handheld miking technique is used when groups sing together, andthey can be either wireless or wired mics. Using so many different mikingtechniques reinforces the need for a good input section on the mixerbecause these microphones are often pushed to their limits. The engineermust maintain control of level, distortion and feedback in multiple mikingsituations. Because the types of vocal performance can change with eachservice, it is crucial for the mixer to have adequate EQ. Often, anoutboard de-esser or compressor is necessary to thwart problems withvocalists, and outboard reverb or other effect devices help embellish thevoice. The audio mixer should allow insertion of an outboard device on thechannel itself or have at least one effect send and return for the entiremix.
Musical instrumentsTraditionally, organs used to be the main source of music, and it wascommon for organs to have their own stand-alone reinforcement systems.Although organs are still widely used, a wide range of musical combinationscan appear in many contemporary houses of worship-from small electriccombos to full orchestras. As the number of instrumentalists increases,more attention must be given to the needs of managing this part of theservice. Number of available input channels at the console should be thefirst consideration. It is not uncommon for a service to resemble aconventional concert when it comes to mixing with many inputs frominstruments and mics. Because there will be a greater need for monitormixes, a console with multiple outputs will also be desirable. The numberof instrumentalists and vocalists will determine the number of inputsneeded, but keep in mind that it never hurts to have too many inputchannels. Because it will be necessary at times to have guestinstrumentalists accompany a vocalist, it is a good idea for the mixer tohave extra channels set aside.
Miking such instruments as acoustic guitars, cellos, violins and a largeassortment of other traditional and folk instruments on the fly is common,and these instruments frequently have internal pickups that are not lowimpedance. It is never wise to run a high impedance line more than 10 feet(3 m) because of interference. For situations where high-impedance sendsare used, it is prudent to insert a direct box as close as possible to thehigh-impedance signal source. The direct box allows conversion from high tolow impedance for better transmission of the signal into the console.
Playing back recordingsMost systems need to have the ability to play back recorded material. Inthe age of multimedia, houses of worship are finding new and creative waysto impact the people attending a service, and recorded media is employed onan increasingly frequent basis. The mixing console selected will need tohave the facility to accept inputs from compact disc and tape players, manyof which are high-impedance devices with RCA-type consumer connectors. Itis helpful if the console has matching RCA high-impedance inputs with again stage to adjust volume of the material going to the mix outputs. In apinch, regular input channels can be used if they are switchable betweenmic and line, but on a smaller mixer, these are often in short supply. Itis generally a better idea to have a console with an accessory inputdesigned for a playback device.
Monitor systemsMany different ways of monitoring program material must be accomplished inhouses of worship. Foldback monitoring is necessary for the musicians tohear cues, and it is sometimes crucial for the podium area to have foldbackcapabilities, especially in large facilities. The most important aspectsfor the musicians are intelligibility of the voice, pitch, tempo and blend.Because of space limitations, the monitoring system should often becompact, which can dramatically affect sound quality. Outboard compressorsand EQs can increase the quality of these mixes when the monitor size iscompromised.
There are also ancillary rooms that are used for overflow during holidayperiods and special events. These spaces, along with dressing rooms,waiting rooms, office areas, hallways, and convertible areas of thefacility, require program monitors. Any of these may require separatevolume levels, so multiple sends and sub-mixing capabilities are essentialon the mixing console.
Because every application differs, laying out needs for different zones ona floor plan of the facility is helpful. Once the number of separate levelmixes for the environments is determined, there are many ways to find sendsfrom the mixing console. Even smaller mixers can provide a variety of output possibilities. If one adds up the number of subgroups, stereo and/or monooutputs, pre/post monitor and effect sends, monitor busses and tape orplayback sends, there are usually enough adjustable output sends to coverthe many needs.
In many cases, it will be necessary to control numerous individuallytailored mixes. For example, the pianist will have different monitor mixneeds than the vocalist. An overflow room or hallway distributed ceilingloudspeaker system requires a full mix of all channels, which is often anentirely different mix than the one sent to the main feed for thesanctuary. It is important to determine just how many monitor mixes will benecessary and how much flexibility of control will be needed before aproper mixer can be chosen. In larger facilities, it may be necessary tohave a completely separate monitor console solely for handling themonitoring load. In other applications a small console with outboard mixeror on-board matrix mix will give enough flexibility to accomplish the task.
RecordingRecording services is growing in importance, as many people wish toexperience again special family events, sermons, and musical performances,or to distribute tapes. Many houses of worship are installing sophisticatedvideo and audio production systems, allowing full production of programmaterial for internal use and broadcast distribution. In manyinstallations, all that is needed is a regular two-channel recordingdevice. Having a sub-mix output channel on the console is instrumental formaking these recordings because it allows the mix to be faithfullyreproduced as it is mixed. There are times, however, that for effect onemay wish to mix in the sound of the congregation or even create a separateindividual mix totally independent and unaffected by the main system mix.This is usually done in one of two ways: either with tie-lines set upallowing a dual path to a second console or via a monitor/effects mix orstrategically placed mics tied directly into the recording device. Usingthe monitor or effects mix bus allows each channel to have a volume levelindependent of the master output routed to the main loudspeakers. Mostmixers have a mix that is switchable before or after the EQ section of theconsole so the signal can go to the recorder with or without the EQ thathas been set up for the main sound reinforcement system. If the acousticsare particularly good in the facility, it is common to record via wellplaced recording mics routed directly to the recording device or routed tothe console and accessed via an alternate sub output. Whatever the choice,the key is to have a console that allows the flexibility to accomplish allof the mixing needs that the congregation may encounter.
Choosing the right console for the house of worship requires carefulattention to current and future needs. It is certainly easier to outgrow aconsole than it is to have too many features.