MUSIC THEOLOGY LECTURE 23 SOUND SYSTEM SCIENCE

The following is an excellent overview of sound issues for a church, by Dr. Dale A Robbins: “Feedback, unbalanced mixes, volume levels too high or low, or monitors which cannot be heard by the performers are some of the common problems with a system which can literally ruin the atmosphere of a service or the composure of a minister or singers. I’ve seen times where the minister and congregation were more tempted to strangle the sound operator, than in appreciating the sermon or presentation of a service. This certainly is not serving the intended purpose of a sound system and does not bring glory to God.

Rom 10:14 How then shall they call on him in whom they have not believed? and how shall they believe in him of whom they have not heard? and how shall they hear without a preacher?

[Do not cut corners with a sound system. The main reason the people have gathered in that auditorium on any given Sunday is to ‘hear’ something; specifically, to hear the truth of God. Yes, they see some things too, but the hearing is the paramount concern they have. Therefore, the quality of that hearing needs to be the best that can be had. If someone cannot hear clearly in the back, then the truth is not getting to them properly. If the folks in the first few rows are slammed with a volume that is uncomfortable, they will tend to not focus on the words, but rather on the volume, and the discomfort therewith. Get it just right…or at least as right as is reasonably possible. Most pastors seem to show little concern with the sound system. Many times they will say (pridefully): “I’ve got a loud voice, so I don’t really need a microphone.” There has only been one preacher I have ever heard that really didn’t need a microphone because of his high quality volumonous voice…Dr. James Wilkins.] (quote by Church building acoustics D. Warner) Operation of the sound system has to be rehearsed, just as singers and musicians do. The operator should be present for all rehearsals of the choir, orchestra, drama group, or similar events. He should make a chart of channel volumes and adjustments which sound best in rehearsals so that they can be easily duplicated during a performance. If there is no formal rehearsal for a vocalist or preacher, a “sound-check” must always be conducted sometime prior to a service, in which all mics and equipment are tested, and all sound levels are adjusted and verified. Excessive guesswork and “flying by the seat of your pants” during the service can produce many embarrassing errors which can devastate the sensitive mood of a congregation or hinder their reception of ministry.

[Here is the ‘classic’ description of the ‘sound guy’: unkempt, out of shape, shirt untucked, fadish hair style; doesn’t typically want to listen to the preaching; only position that he is ‘qualified’ for; wants to be in charge of something; doesn’t have a submissive heart; and will leave the church if he doesn’t get to ‘do the sound’.] (quote by D. Warner)

The sound controls and operator must be placed where he can hear the same acoustic environment that the congregation hears. A open air, box-seat enclosure equipped with sound mixer, in the approximate center of an auditorium or balcony is usually the most effective format. Because of prohibitive costs, it is rare to find a church which has the highest quality microphones and audio equipment, and most churches are notorious for building designs which produce poor acoustics. Complicated by volunteer personnel which usually have little or no training with audio technology, it is easy to realize why churches often complain about their sound. People who are accustomed to the professionally mixed sounds of records, tapes and video expect the same results in their church. But this high quality can only be achieved with: (1) Properly installed, high quality microphones and audio equipment, (2) a favorable acoustic environment, and (3) knowledgeable and experienced technical operation of the sound system.

1 As it seems to be in most other aspects of a church, there is a diversity of opinions about how the sound system should be operated. You will discover that when the volume level is satisfactory for most, there will still be some who cannot hear well and others who will think it’s too loud. Unfortunately, a sound operator cannot always accommodate every hearing sensitivity. All he can do is try to gauge the volume to an acceptable level for the average listener. A sound operator should have a “few” selected spotters in the audience that can help him gauge volume levels from different locations, but he should avoid being manipulated by the numerous diverse opinions.

A decibel meter is helpful in gauging volume in a auditorium. But even though the volume levels may be set identically during each service, the perception of loudness will be affected by the quantity and seating assignments of the persons in attendance. The presence of each person has an effect on the acoustic environment. A larger crowd will require more volume — a smaller attendance will require less volume. An established system of hand signals is generally the best method of communication between the person on stage and the sound operator.

1 Cor 14:40 Let all things be done decently and in order.

There are three basic pickup patterns used by most microphones: Omnidirectional - Sensitive to sounds from all directions; Unidirectional - Sensitive only in one direction, usually a cone shaped pattern; Cardioid - A type of unidirectional mic, sensitive in one direction. It picks up sound in a heart-shaped pattern, strongly from front, and about half as loud from the sides. A hard-wired mic is the standard type of mic which has a cable wired directly into a sound control board. Most mics used today are of a low impedance type (low resistance) which are resistant to interference and allow longer cable runs. A lavaliere (or lapel) mic is tiny, hardly noticed mic clipped on a person’s clothing, great for amplifying speech, but not so good for the broad dynamic range of singing. Some preachers love these because they leave the hands free and no cords to dangle — others hate them because the sound is not as good as a larger, hand-held mic and there is no dynamic control over the volume (by lowering and raising the mic). When used for vocal amplification, a microphone should be mounted or held within a tolerance of between 3 and 8 inches of the person. To keep a mic within these tolerances, a gooseneck or boom can be used on a stand or lectern to adjust the vertical/horizontal placement. When holding a microphone during singing or preaching, it’s best to hold your mic approximately 3 to 4 inches under your chin. During moments that a microphone is not being used, it should never be held randomly in any direction. If the mic is still “live” and not used, it should always be held in an upright position, lowered from your mouth if so desired until you need to use it again. Due to the concern in delivering sufficient power to the monitors for the singers to hear themselves, the “feedback” threshold is often stretched to its limits. By inadvertently pointing the mic toward or near a speaker may create shrill feedback. There is another problem which is caused by holding two or microphones too close together. This is called “phase shifting,” and creates unpleasant, unnatural sounds. It is advisable to never allow two live mics to come closer than two feet from each other. Don’t blow into a mike to see if it’s on. This sound is annoying and you might blow harmful moisture (spit!) into it. It’s a better idea to say something or tap it lightly with your finger. Do not speak directly into a mic. You’ll usually create a popping sound, especially if you make a “P” or “T” sound. A wind screen on the mic will help to reduce this, but it’s best to improve technique by speaking across the mic rather than into it. Do not wear or handle a mic when you step into a baptistry. A hard-wired mic may deliver a serious electrical shock to a person grounded in a pool of water.

When a church has a simple system which delivers sound only toward the congregation, I refer to this as a single phase system. However, a system which also includes separately controlled stage monitor speakers (also called fold- back speakers) for performers to hear themselves, would be considered a two phase system. Monitors are essential in larger churches, or especially when a performer cannot adequately hear his own sound coming over the PA to the congregation.

Feedback is technically known as audio oscillation. In simple terms, it is nothing more than sound coming out of the speakers, going back into the microphones and reamplified in rapid oscillating cycles, creating a shrill whine or squeal. The object of a system is to achieve satisfactory, high fidelity amplification of sound before feedback occurs. Under some circumstances, limited by acoustics and poor equipment, this can be a real challenge. There is no complete cure for feedback. If the volume of any mic is boosted loud enough, it will eventually cause feedback. However, these are ways that it can be reduced and controlled: 2 Methods to Reduce feedback: 1. Turn the volume down. 2. Decrease gain on equalizer (EQ) or tone controls. 3. Reduce monitor system volume or its EQ gain. 4. Move microphones farther away from sound path of speakers. 5. Use higher quality, low impedance microphones and equipment. 6. Select tighter patterned, cardioid microphones when possible. 7. Decrease gain on reverb controls. 8. Improve room acoustics to absorb more reflected sounds.

Tips on Reducing Interference: Radio frequency interference (RFI) can bleed into sound systems from nearby radio stations, or C.B. radio transmitters. Electro-magnetic frequency (EMF) interference can also come from other electrical devices such as electrical transformers, fluorescent lights, computers, electric motors, or switches. High impedance microphones and equipment are much more sensitive to these types of interference. In some cases, interference in such systems can be reduced by using shielded microphone and input cables, and reducing their lengths. If possible, the best solution is to convert to low impedance, balanced mics and equipment, making certain that all mic and input cables and connections are well shielded. Low impedance systems are more resistant to interference. If interference is detected, it’s often due to some defect in a shielded cable or connection somewhere in the input side of the system which can be traced and repaired. Grounding problems can be another common cause for PA interference. If your control board and amps are equipped with a three pronged, grounded AC plug, make sure that the electrical outlet is properly wired with a good ground connection. If electrical “buzz” still occurs, some amps or mixer boards have polarity switches that can be reversed, which by experimentation may help reduce or eliminate some electrical noise. If problems persist, consider that the problem may originate in one of the components in your system. Remove individual components (such as equalizer, limiter, etc.) one at a time, and see if their removal eliminates the problem. If no success, try temporarily lifting the ground at the electrical source to see if the “buzz” disappears. If so, this will usually confirm that it is a grounding problem somewhere in the system.” (end quotes from Dr. Robbins) Sound mixer science will not be discussed in this lecture (due to the teacher’s total ignorance on the subject!). Here are some further excellent ideas and facts for sound system science by Lindsay Terry: ●“Keep speakers ‘subdued’; don’t have them stand out like they would at a ‘Rock concert’. Obnoxious looking speakers will detract from the holiness of the church sanctuary and make it look worldly. ●The sound should be amplified as such to give the impression that the one who is singing/playing/speaking is only about 18 inches away from you. ●The worse shaped building for sound would be one that has rounded walls with a domed ceiling. The best is one with carefully placed angled walls with sound reflectors on a medium high ceiling. ●There are different mikes used for different venues: soloist, choir, preaching, piano, other instruments ●The volume needs to be loud enough so that a ‘cough’ in the audience doesn’t drown out what is going over the speakers. ●Sound levels in an empty auditorium won’t be the same when it is filled with people. It is estimated that one body absorbs as much sound as a 4 foot open window. ●Always keep all mikes in the ‘on’ position for a particular service. Control the volumes from the ‘slide’ controls on the ‘mixer’. This will help avoid embarassing oversights with a singer not having their mike ‘on’. ●Always start with the gain/volume on the high side (but not extreme) and then cut back once the person begins speaking/singing; this is better than the opposite (too low and then bringing it up to the right level). ●When eyes are closed, turn your head to the source of the amplified sound. When you open your eyes, you should be looking at the person speaking or in their direction from any location within the sanctuary. ●All microphone lines shall be continuous from the platform to the mixer position without any breaks. (Multi pair cables have a high failure rate. If you have to use a multi pair cable or snakes make sure the mic pairs that are individually jacketed) ●Provide a minimum of 1 mic input for every 60 square feet of the pulpit/ platform/ altar area. This will ensure enough mic locations for the choir and all special events. (end of Lindsay Terry’s quotes)

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