When we connect an acoustic guitar to the mixer, it sounds "thin" and "tinny".
When a passive pick-up is used in an acoustic guitar, the sound from the pick-up is often "thin" and "tinny". This is because the pick-up is much more sensitive to the high frequencies than it is to the low frequencies.
Because of this, you hear too much of the high harmonics and you lose the low harmonics. Usually, the amplifier or mixer you connect to won't have enough EQ or tone control range to regain the natural sound of the guitar.
You need an instrument cable that has a built in low-pass filter which corrects this problem. This type of cable will reduce the high harmonics, producing a more natural guitar sound for the amplifier or mixer.
We seem to always be getting feedback in our church sound system. How can we eliminate this?
What Causes Feedback
Feedback occurs when a microphone is amplified enough to cause it to pick up sound from the speakers and generate a loop: the speakers feed sound into the microphone which in turn supplies sound to the electronics which feed the speakers, and then the mic picks up that output and keeps the process repeating. This loop of sound creates that loud, annoying squeal that everyone dreads. Feedback will always happen at a certain frequency (or pitch) depending on which frequency resonates the most readily in your room.
How to Eliminate It
First, make sure that your room has been properly tuned. This is a process that is done during installation setup. A real-time analyzer is used to determine the resonance of various frequencies in your room and a 15- or 31-band graphic equalizer is then adjusted according to the results. This will ensure that your audio system produces output that sounds equal in power at all frequencies, taking the room's characteristics into account, which allows you to get more volume out of the system before feedback starts being produced. It also gives you the most accurate sound reproduction for your room.
Placement of the Microphones
The previous process eliminates the most problematic feedback issues, but you can still get feedback if you set the levels high enough. Don't panic! Your next job as a sound tech is to make sure that the placement of the microphones is correct. Most mics are designed to pick up sound within a 60-degree radius. (Make sure you check the data sheet if you are unsure.) Use this to your advantage. Try not to place the mics such that they face into any speakers. This way the speakers would not project their sound into the microphones. Also, instruct anyone using the mics to stand close to them (about 3 to 6 inches away). That way you won't have to crank it up to get the needed volume and increase your chance of getting feedback.
Presetting the Levels
Setting your levels properly and knowing your feedback limit is important. When setting up a microphone, it can be useful to drive it into feedback. This reveals the maximum levels for your settings. In a production environment, stay below this level at all costs. If someone is speaking too low or is too far away from the microphone, then it is the fault of the person speaking, and not of the sound operator. The sound system is half of the battle and sound techs need to do everything they can to ensure a clear transmission, but good communication skills are the other half of the battle that usually gets left out of the picture when something goes wrong.
Turning Off What You're Not Using
Another common mistake that encourages feedback in your church sound system is leaving microphones on when no one is using them. It's not always wrong to do this, depending on the situation, but if you can, turn any mics off completely when not in use. Here's a scenario: The worship team has finished the final song before the message. Three or four mics are left on at the front, and the preacher gets up to give his sermon. While he is speaking, an annoying ring can be heard slightly when he says certain words. That annoying ring means that you are on the threshold of going into full feedback. You try turning the channel on his microphone down and finally get rid of the ring. BUT you just cut his level down! Try turning off the other mics instead, and you probably won't have to touch his level at all.
Always keep your ears peeled, listening for that slight ring. If you hear this and you've already turned off any unused mics, back off on the volume just enough to get rid of the ring. This might make it harder for the people at the back to hear the words, but if you don't, the ring will distract everyone from the words.
If you are using your sound system as a "turn-key" system (which means that you just turn it on and off) and you don't have a sound operator, or if you want to get the highest possible gain before feedback, especially with a lapel microphone, you might want to consider a feedback eliminator. This is an electronic processor which searches for and destroys feedback. There are many different ones available from manufacturers such as Shure, Behringer, and Sabine. Currently, a popular solution is the AFS224 from DBX due to its balance of cost and performance.
Can I connect speakers to my amplifier through a snake?
Stage monitors are an important part of your church sound system setup. If they are not connected properly, the results can be disastrous. If your power amplifier is located at the front of the room with the speakers, it's fine to feed your mixer output through the snake to the amplifier. If however you are sending the amplifier speaker output through the snake to the speakers, this is not good. The snake is made for low-power line-level or microphone-level signals, not powered speaker signals.
Reasons For Not Sending the Amplifier Output Through the Snake
The size of wire used in a snake is too small for powering speakers. Doing so would result in considerable heat and power loss. This means that you will get less sound out of your speakers and potentially create a fire hazard.
The impedance of the wire is wrong. Speaker cable is unshielded but the snake wire is shielded. Shielded cable has more capacitance and inductance and therefore will distort the frequency response of the sound.
Because the amplifier outputs a much higher voltage and current than a microphone signal, there is crosstalk from the amplifier signal back into the microphone lines. This produces a form of feedback from the amplifier output back into the mixer inputs through the microphone lines which can cause phase shifting of the signals. Your ears may not notice this unless you listen very carefully, but your amplifier won't like it (see next point).
Due to the close proximity of the high-powered output to the sensitive mic-level inputs, an ultrasonic inter-modulation usually occurs. This produces a high-frequency oscillation (too high for your ears to hear) which can damage your amplifier.
Remember: Snakes are made for low-level signals and should therefore only be used for such. You can run line-level from the mixer to the amplifier input through the snake, but not speaker-level. So always remember to run proper speaker cables from your amplifier to the speakers.
We need to connect musical instruments to our sound system. How should we do this?
A musical instrument such as an electric guitar or electronic keyboard uses a high-impedance unbalanced output. This is designed to operate effectively at a maximum distance of 15-20 feet without picking up hum and electrical or radio interference. If you have a short distance from the instrument to your mixer, or you are operating in a very interference free room, you might be able to plug the instrument directly into a line-level input on the mixer using an instrument cable with 1/4 inch headphone connectors on each end. This cable must be a shielded instrument cable. Don't try to use an unshielded speaker cable.
Converting the Instrument Signal
For permanent installations or greater distances to the mixer, you need to convert the instrument signal from high-impedance unbalanced line-level to low-impedance balanced microphone-level. This can be accomplished in one of two ways. The most common method uses a direct interface box (DI box). The instrument is connected to the DI box using a standard instrument cable with 1/4 inch headphone connectors on each end. The DI box is then connected to a microphone jack using a standard microphone cable. By converting the signal, you greatly reduce the possibility of picking up interference and make the instrument look like a microphone to your mixer. If you want to also feed sound to a guitar or keyboard amplifier, some DI boxes have a second unbalanced output which will do this.
Direct Interface Boxes
A couple of popular DI boxes are the DB25 (passive) and ADB2 (active). Both have unbalanced instrument inputs and unbalanced line-level and balanced mic-level outputs. Both have attenuation and ground lift switches. The ADB2 active box has a very broad frequency response from 1 Hz through 50 KHz, while the DB25 covers 50 Hz through 15 KHz. For instruments with very low or high harmonics such as organ foot pedals, the active box might be the better choice. It does, however, require phantom power.
The Direct Interface Cable
Another method is to use a direct interface cable. This performs the same function as the DI box, but requires one component instead of three. The DI25 direct interface cable is a 25-foot cable with a mic connector on one end and a 1/4 inch headphone connector with built-in transformer on the other end. It plugs into a keyboard, guitar, VCR, etc. and converts from a high impedance unbalanced signal to a low impedance balanced mic-level signal. The other end plugs into a standard microphone jack. This cable enables you to plug any instrument into any microphone jack without picking up hum and electrical interference.
The DI25 cable saves you money and setup time. It is also more immune to interference since it converts the signal directly at the instrument output instead of at the box end of the instrument cable. If you want to use a local amplifier for the instrument, you can connect from the instrument to the amplifier, then from the amplifier's "pre-amp" or "line" output to your microphone jack using the DI25 cable.
I can't get enough volume from our mixer to the tape or CD recorder. How can I fix this?
Using an Auxiliary Output
In order to get sufficient volume for good recording levels, your mixer needs to be operating at higher output levels than you usually use for live sound, especially in a church setting. In order to get around this, you can use an auxiliary output if there is an extra one available. By doing this, you can increase its level to what you need for recording. This gives you the added feature of a separate mix for recording. This separate mix can be an advantage because you can now feed as much of each microphone as you need to tape, independent of the main speakers. It can also be a disadvantage because you need to monitor what you are recording more carefully since it is not what you are hearing in the room. It is also difficult (even impossible in some cases) to get a stereo recording this way.
Using a Preamplifier
The second, simpler choice is to add a stereo line amplifier to the system. This unit simply connects between the output of the mixer and the input to the tape recorder. It boosts the signal up to the level required for good quality tape recording.
What do typical church sound systems include?
Church sound reinforcement systems include the following items to make up a full installation package.
- Microphones (wired/wireless)
- Mixer/Amplifier or separate mixer, equalizer, and amplifier
- Main Speakers
- Wiring to interconnect the components
We also offer additional items for church sound reinforcement systems such as:
- Tape deck for playback/recording
- CD recorder and/or player
- Monitor speakers and in-ear monitors for singers, musicians and choir
- Hearing assistance
- Fill-in speakers for under balcony seats
- Rear fill-in speakers for long rooms
- Distribution speakers for foyer/lobby and other rooms
- Sound feeds to video system
Please note that Master Audio Visuals, Inc. custom-designs every church sound system. We account for all your present needs and also try to anticipate future requirements. If you would like us to help you design a system for your church, please contact us.
Some people in our congregation have hearing problems. How can we help them?
A Comparison of the Types of Hearing Assistance Systems
As far as hearing assistance systems are concerned, there are basically four types of systems for this application. The pros and cons are as follows.
One approach is a wired system. This consists of permanently installed hearing stations mounted on pew backs. This method is obsolete and would need to be custom-built. When you consider that the units would be costly to build, and a considerable amount of labor is required to install it, this is an expensive approach. Combine that with the fact that people can only sit where there is a station, and it is easy to see why this is not a practical choice.
Another old type of system is the "loop". This is a wire which surrounds the room. It acts as an antenna, transmitting to hearing aids. Although it is still used with some success, it is also obsolete. This method requires each listener to have a hearing aid with a "telephone" switch, it is only useful in the room which it is installed in, and is prone to electrical noise interference. Installation of this system is also quite expensive, critical and often unreliable.
A system which is quite popular in theaters and lecture hall translation applications is the infrared system. We don't recommend them to churches. The system consists of a power unit which is usually located near the amplifier. It is wired to an emitter installed on the ceiling or wall. The emitter transmits to any number of "under chin" receivers in the room. This is fine for most theater applications but presents problems in churches. Since the system requires line-of-sight visibility, the receivers must always be able to "see" the emitter. The signal is blocked if people stand up or turn around. Although the users can sit anywhere they can see the emitter, the system is usable only in the one room. The receivers are also very conspicuous. The cost of the infrared system is also higher than the radio systems.
The type of hearing assistance and translation we recommend to churches is a radio frequency (RF) system. This consists of a transmitter which connects directly to your mixer (or microphone for translation) and pocket receivers for the people who need them. The sound from all your microphones is transmitted to the pocket receivers so that everyone can hear everything through earphones. The system offers many earphone and neck loop options. Everyone has their own receiver with volume control. Because the system uses radio waves, it does not require line-of-sight visibility; thus, people can sit anywhere they like, even in other parts of the building.
How do we determine what microphones are best for our church applications?
There are thousands of microphones available of various qualities, designed for many different purposes. Most microphones can be divided into two quality classes and a few different style categories.
Professional vs. Consumer Microphones
Consumer companies do not usually make any products which are up to a professional standard of quality. Some of the professional companies only make professional products, and others make both lines of products. The consumer products sometimes have "professional" in their name, which is often a dead giveaway that they are not. Unless you know the industry, it can be difficult to know the difference just by looking at it.
Recognizing and avoiding consumer products can be a difficult task since some salesmen are under the impression that their lower-quality microphones actually meet professional standards. It is best to deal with someone who has experience and is seriously involved with professional audio. It is also a good idea to avoid stereo and electronics shops because they generally do not sell professional microphones. However, most higher-end music stores will carry both. Keep in mind that professional microphones are not necessarily expensive -- they just work much better.
Finding a Microphone Designed to Fit Your Application
Different microphones are designed for different applications and although some types might be interchangeable, each type works best when used as intended. It is your task to find the microphones that are not only high-quality but also designed to fit your applications and needs.
Pulpit and Lectern Applications
For a pulpit or lectern, it us usually best to get a good gooseneck microphone and install it using a shock mount to reduce sound transfer from the wood into the microphone. You need one with a deep pick-up range so that it will work effectively at the various distances required. Although you could use a hand-held style of microphone, you would need to be very careful to get one with a very low proximity effect. Most hand-held microphones are designed specifically for close use, and therefore are insufficient for pulpit and lectern applications.
For permanent choir applications, there are tiny microphones which are designed to hang from the ceiling specifically for this purpose. Like the pulpit microphone, they need to have a deep pickup range.
Choir microphones should be installed about 2 feet in front of the front row and about 2 feet above their heads. Assuming the choir is 2 or 3 rows deep, you will need 1 microphone for each 4 to 5 people wide. For example, if your choir is 8 people wide and 2 rows deep, you will need two microphones. If the choir is 4 or more rows deep, you should add a second set of microphones to pick up the back two rows.
If you need to mic a choir on an occasional basis, or if they are not always standing in the same location, you can consider placing microphones on boom stands in the same locations as described above. You can use gooseneck microphones, like the ones for pulpit and lectern, or low-proximity hand-held microphones as described below.
If you need to mic a group of people (singing or speaking), it is best to use low-proximity microphones on stands. Unlike most hand-held style microphones, there are some that will give a very accurate sound at any distance. This makes it perfect for picking up two or three singers, or a group of people in a skit or play.
Solo Vocal Applications
If the microphone is only for close-up vocal use, there are many models which will do a good job. Keep in mind, however, that most vocal microphones are effective up to 3 inches. Beyond this distance they become thin and tinny sounding. This can be a problem for churches, because church singers often don't hold the microphone close.
If you want a more versatile and forgiving microphone, you should choose a low-proximity model. With ith a lapel microphone.
The alternate method of course is to use a good lapel microphone. The microphone should be placed in the centre of the chest about 6 inches below the chin. Be careful that it doesn't get covered by, or rub against clothing.
Altars and Communion Tables
If there is only one person speaking at the table, then a wireless head or lapel microphone is the best way to go. If you have more people, or don't want to use wireless, you can either use a gooseneck microphone (as on the pulpit) with a short table stand, or a flat boundary microphone like the one you see in pictured to the left.
How do we determine the best mixer for our application?
The mixing console or mixer is at the center of your church sound system. This is the unit that accepts various types of inputs such as microphones, instruments, cassette decks, CD players and more. It then allows you to control and mix the sound and send it off to a wide variety of different areas. These areas may include:
- Main Speakers
- Monitor Speakers
- Distribution Speakers (nursery, foyer, etc.)
- CD or Tape Recording
Master Audio Visuals, Inc. installs several lines of professional mixers. As with speakers and microphones we make our selection based on value and performance. We watch the market and carefully test and evaluate new products which appear to be of interest. We compare their sound quality, features, background noise, reliability, ease of repair, as well as price. This way we can weed out the good from the not-so-good.
Our church sound customers require a wide range of equipment. Some only need three or four microphones using a basic 5 channel mixer/amplifier. Others require a 24 or 32 channel mixer with subgroups, signal processing and stereo main speakers, several monitor mixes, and multi-track recording capabilities. Of course, there are also many with requirements in between.
We need a monitor system for our worship team. What type should we choose?
Working With Stage Monitors
Monitor problems in church sound systems are a very common concern. They provide a great opportunity to destroy the sound for the congregation and create feedback.
A full-range monitor is usually a two way speaker with a woofer and tweeter. It has a full range of frequency response in order to reproduce the low, mid, and high frequencies. It therefore gives a you a full and reasonably accurate sound. This can create problems though.
The purpose of a monitor speaker is to give the musicians and singers the reference sound they need to keep in tune and in time. A compact reference monitor can accomplish this without producing the problems associated with a full-range monitor.
This technology is very popular in professional shows, and is an excellent solution for church monitor problems.
Aviom Personal Monitor Mixing System
The Aviom system enables every singer and musician to control their own personal monitor mix.
We want to record our services. Should we use cassette tape or CD?
If you are adding new recording equipment now is definitely the time to record on CD instead of tape. Here are the reasons why:
- More people can play CDs than they can tapes. A few years ago, people used to say "I want a tape so I can play it in my car" -- but now they want CDs for that purpose instead. Even seniors are saying they can't play tapes -- only CDs.
- The quality of CD recording is far superior to cassette tape.
- The life of a CD is far longer than that of a tape.
- The cost of a CD is lower than the cost of a cassette tape.
- The cost of a CD duplicator is less than that of a cassette duplicator.
- A CD duplicator will copy a CD twice as fast as a cassette duplicator will copy a tape.
- Cassette tapes are almost extinct. When is the last time you saw tapes for sale in a music store? There are very few consumer cassette recorders made now. A professional cassette recorder is almost as expensive as a CD recorder with similar features.
We want to record CDs of our service. Can I use a computer or consumer recorder?
Computer CD Recording
We have a few customers who have tried to use their computer to record. Here are some of the problems they face:
- Computer recording is not a very simple process. It cannot be done very successfully by someone who is inexperienced in this area. If you have more than one sound operator, the success rate is likely to vary significantly.
- Computers are prone to lockups and crashes. This, too, will affect your success rate. This effect is greater if you use the same computer for another function at the same time.
- Computer sound cards are very simple. They don't have the head room, compression and quality of pre-amps found in proper CD recorders. It is sometimes very difficult or impossible to get decent sound quality during live recording.
Consumer CD Recorders
There are a few consumer CD recorders on the market, but they are a poor choice for a church. Here are some reasons why:
- Since they are intended for consumer use, they often have copy protection built into them which limits the number of copies you can make.
- The features and quality of electronics and mechanics are not up to professional standards.
Professional CD recorders are excellent quality, have no copy protection, and will record on almost any blank CD-R or CD-RW.
I am considering a head microphone to get the best sound quality without feedback, but our preacher doesn't want to look like a rock star.
Although lapel microphones provide freedom of movement, a head microphone is really the best choice. Many are available in beige or black and are extremely small and light weight. A good head microphone can provide very natural, high quality sound. The volume and tone never change because the microphone is always in the same position relative to your mouth. You can get plenty of gain before feedback because it is close to your mouth and it is so small and inconspicuous that you and everyone else will probably forget it is even there.
We can't seem to get a good mix for our worship team -- we can't distinguish between the instruments.
Avoiding A "Wall Of Sound" When Mixing Your Worship Team
Many have found mixing a full worship team presents a difficult challenge. In many cases the end result is what we call a "wall of sound", where one instrument can't be distinguished from another.
The "wall of sound" occurs when the operator uses volume as the only tool to mix the band. When mixing, you have several tools available to help blend the sound, however many inexperienced operators are not enlightened on how to use these tools.
The tools that you have are:
By using a combination of these tools we can create a mix where we can hear each instrument independently but still have them blend together.
Placing Instruments In The Mix Using Equalization
Start by listening to the individual instruments and adjusting the equalization controls. Each instrument can have its own space in the mix with regards to frequency. You could adjust the EQ controls differently for each instrument. If you boost the piano at 2Khz, boost the electric or acoustic guitar at a different frequency.
Also compare instruments by listening to two or three at the same time. Try to listen to see if you can hear each instrument stand out from the mix. Don't worry too much if the instrument sounds a little thin on its own. You want to keep it in context of the full mix -- not make each instrument sound wonderful as a solo instrument.
This is known as "placing in the mix". The best is example is the bass guitar. The bass guitar should take up the bottom end or low frequency so we should not boost the low frequency control on the acoustic guitar. Why? Because if we do then the piano overlaps the bass guitar's frequency range and contributes to the "wall of sound".
Making Elements Stand Out Using Separation
This next step only works if you are using a stereo system. Use the pan controls on your mixer to pan instruments more to the left or right instead of leaving everything dead center. This technique helps to make it sound as if there is physical space to your mix.
Some people worry that by panning an instrument more to the left or right that only the people on that side of the room will hear that instrument. However you can still hear that instrument quite well on the other side of the room.
Use the same principle that you learned for equalization. If you pan one guitar slightly left then pan the other guitar slightly right. This provides more of a physical space separation.
Adjust The Levels Between Instruments
Now that we have effectively used equalization to place each instrument in the mix and used panning to provide more of a physical separation, we can set volume levels for each instrument and vocal. A good technique is to look at each instrument and singer one at a time, and listen to make sure you can hear them.
Make sure the vocals are above the instruments. If you have sub groups on your mixing console you can group the instruments to sub groups 1 and 2 and the vocals to sub groups 3 and 4. This will give you greater control by allowing you to control all of the instruments with 2 faders and all the vocals with 2 faders.
Getting a great mix from a worship team doesn't have to be a daunting, impossible task. In fact it can be one of the most fun and rewarding experiences as a sound operator. By understanding and using the mixing tools at your disposal, you can avoid the "wall of sound" and create a better mix of your worship.