Newsletter Archives   July 2005 Cutting your way through the Wireless Jungle Wireless mics are everywhere in today’s churches, whether just being used for miking the pastor as he preaches or for large groups of performers or singers.  There are hundreds of choices in wireless systems and mics to choose from, how do you decide? We will explain the terminology of wireless mics and provide some pointers for selecting the right one for your needs. Wireless mics are not toys-You can not buy cheap, good wireless mics. I can not begin to tell you how many cheap wireless mics I have found in drawers or under pulpits. These mics worked for a little while but do not provide long term service. Plan to spend at least $300.00 to $500.00 per wireless mic system.  Diversity vs. Non-Diversity-Diversity system receivers have two antennas. The receiver is constantly checking the antennas for the strongest signal. The receiver selects the best signal for transmission and rejects the weaker signal. Non diversity systems have one antenna. Therefore, if there is interference you are stuck with it. The answer here is simple-do not buy non diversity systems. Many people come in looking for dual mic systems. Most wireless systems that will accommodate more than one mic are simply two or more non-diversity systems packaged in one box. Once again, they are not dependable. VHF vs UHF-These stand for Very High Frequency and Ultra High Frequency. VHF is generally around 175.00 to 225.00 megahertz and UHF is around 550.000 to 700.00 mhz. What does this mean to you? The VHF band is very crowded with radio signals of all types, especially in urban areas. I recommend that churches in urban areas do not buy VHF wireless mics. We have even discontinued selling VHF for this reason. UHF is much more dependable and less susceptible to interference. Some TV stations broadcast on UHF so be sure not to buy UHF wireless that are close to the local TV broadcast frequencies. Most local stores stock wireless which are compatible with local stations. If you buy a wireless at a store in another city it may not work in your town. One way to avoid this is buy wireless that is Frequency Agile. Frequency Agile-Wireless mics are like the radio in your car. The receiver must be tuned to the same frequency as the station. Imagine that the mic is the radio station (transmitter) and the receiver is the radio. Just as your car radio can only pick up one station at a time a wireless system can only operate one mic at a time. Some wireless are fixed frequency, meaning the mic and receiver are set to a fixed frequency that can only be changed by sending it back to the factory. Frequency agile systems allow the user to change the frequency easily. Why do you need this? If your wireless starts to pick up interference or “drop out” occasionally you may change the frequency to one more dependable. Also, if you plan to add more wireless later you can dial them all in to different frequencies. Some wireless also have a scan feature which will scan for the clearest frequency. Frequency agile systems may have from 10 to several hundred frequencies from which to choose.       August 2005 Recording your Church Service   There are many reasons to record your church service: ministry to shut-ins, sale to members, website posting and just saving for posterity are a few. No matter which, there are a few tips that can help you get the best recording for your ministry. The first thing to note is when recording through the sound system, only the things that have mics on them will make it onto the recording. For example: If you have a choir singing, using choir mics for amplification, and an organ playing which is not miked into the sound system, your recording will only have the choir and whatever sound from the organ happens to bleed into the choir mics. The same goes for audience participation. The congregation will not be recorded unless a mic is present to record them. So, the first step is to mic everything you want recorded. This could be from a single mic on the preacher to record the sermon to a mic on every instrument and singer in a praise team. By the way, a good way to mic congregations is to use a large diaphragm condenser mic at the rear of the church. This is easy and fairly cheap. We sell a pretty good one for $49.00. Now that everything is miked you have to determine how to hook up your recorder to the sound system. The recorder needs to be hooked to the mixer. There are several ways to do this. I will cover the pros and cons of each. Generic tape output -Many mixers have a "Tape out" connector-usually stereo rca connectors. This is the simplest way to hook up your recorder. It will usually give you an exact copy of the main output of the mixer. This is ok for simple recordings like sermons. The downsides of these are they often have too low of a signal resulting in poor quality recording and if you are recording more than one input you can not adjust the level of each independently. Other Main Outputs-Most mixers will have additional outputs to the main house out. Some may be labeled main out, monitor out, sum out, control out or other similar terms. These can be better than a Tape out because you can adjust the level of the output to get a good signal at the recorder but you still don't have the ability to adjust individual channel levels. Aux out-Using one of your mixers auxiliary outputs is a way to get a very good recording. This allows you to adjust the master level going out to your recorder as well as adjusting the individual level of each input. This means that you can record a choir with a lead singer singing with several instruments and adjust the level of each to get a well balanced recording. The down side of this is that it is not a "set it and forget it" solution. Your sound person will actively have to adjust the record levels as needed. Direct out-This is the best and most complex way to record. I recommend this method only if you are seeking true pro quality recordings. It involves using a multi-track recorder to record each input separately from a direct output on your mixer. You can later go back and mix your final product as desired.   Recording your Church Service-Part Two Last month we discussed micing items to be recorded and how to hook up a recorder to a mixer. This month lets look at the different types of media used to record. The old standard recording media is cassette tapes. These were common for a very long time but are going out of style due to the popularity of CD's and other digital media. If you have cassette only now I recommend switching over to CD soon. CDs are the most popular today for recording and copying. Most people have CD players in thier cars or homes. CDs can hold up to 80 minutes of content. CD burners and copiers are not too expensive and fairly easy to use. If you are going to use the recording on a website I recommend recording to a computer harddrive and using a wma or mp3 format. This will allow you to edit and store the files and broadcast them easily on the internet. You can also make cds from these files. If you are recording a large group and want to remix the recording you need to record to some type of multitrack recorder. There are several types of multitrack tape recorders but you probably want to use a hard drive type. This will allow you to remix, edit and produce the final copy from one machine. When recording it is important to set the proper recording level. When recording to tape watch the meter and set the level so that it approaches and even ocassionaly enters the red zone. If the level is set too low you will get a lot of tape hiss. If it is too high (constantly in the red) you will get a distorted sound. When Recording to cd or other digital media it is important to never allow the signal to enter the red zone. This will cause digital distortion which sounds awful!!     Selecting a mixer The audio mixer is the heart of your sound system. It is the control surface that turns on and off all the mics, musical instruments and other audio sources. It adjusts each inputs level in the main speakers and monitor speakers. It also adjusts the equalization for each individual input. If your mixer is not up to your needs then your whole sound system will suffer. So how do you go about selecting a mixer? The number one rule is buy something you can grow into. If you buy a mixer that will exactly meet your needs today the chances of you outgrowing it in the next couple of years are very good. For example: If you are using 6 stage mics, 2 wireless mics, 2 choir mics and 2 inputs for tape/cd then you need a 12 channel mixer. You should go ahead and buy at least a 16 channel to allow room to add more inputs later. OK, the first criteria you should look at is the total number of channels needed. One channel is need for each input. Inputs are: Stage mics, choir mics, wireless mics, musical instuments and audio sources like tape, cd or audio from a video player. Each source needs its own channel. Get a mixer that has enough channels for all your inputs plus a few extra. Now let me warn you that mixer marketing is very deceptive. Do not go by the model number or even what a salesperson tells you. Look at the mixer and count for yourself how many channels it has. Many have a combination of mic channels and stereo channels. The stereo channels can be used for tape/cd players etc. Count your mics and other devices and then count what the mixer has and be sure you have enough. The next criteria is outputs. These can be divided into auxillary sends and main outputs. Lets talk about the main outputs first. Any mixer will have at least 2 main outputs. These send the signal to the amplifiers that drive the main speakers. Some mixers will have additional outputs which can be used to drive speakers in other parts of the building, delay or balcony fills etc... Determine if you have speakers to drive other than your main speakers and select a mixer with addtional outputs. There are other ways to drive these additional speakers. If you have a lot of other speakers you should talk to a pro about designing the best way to drive them. Auxillary sends are outputs that are controlled independently of the main speakers. Some examples are: monitor mixes, effects loops and recording sends. To determine how many you need count how many monitor mixes you need and whether you need to use any aux. sends for effects loops or recording. For example: If you have a choir monitor mix and a pulpit monitor mix plus a reverb and tape record you need at least 4 auxillary sends. Next month-More Mixer Selection: Subgroups, EQ and Powered vs Nonpowered. Please call Sound Services (205-595-4530) with any questions.     Selecting a mixer-Part 2 Last month we discussed how to choose a mixer with the features and size you need. This month we will discuss powered vs non powered mixers, subgroups and eq. Powered vs NonPowered -Any basic sound system consists of a mixer, amplifier and speakers. A powered mixer simply is a mixer and an amplifier built in the same package. This allows you to plug your inputs (mics, music etc..) into the front, your speakers into the back and you are ready to go. A non-powered mixer requires the addition of an external amplifier between it and the speakers. Powered mixers have thier place. They are handy when a small, portable system is needed; classrooms, rehersal rooms, small club acts or small churches. They do have several drawbacks and I only recommend buying one when these are not an issue. 1. They generally have small amplifiers and can only operate 2-4 speakers. Some will have 2 amplifiers built in which allows you to run mains and 1 monitor mix. If you need to play really loud music or have a large audience they will not suffice. 2. They usually have limited aux sends which only allow 1-2 monitor mixes. If you need several monitor mixes they will not suffice. 3. The onboard eqs are usually limited. If you need to fine tune your system these eqs will not do. Generally speaking-if you only need to operate a few mics in a small area and monitors are not an issue a powered mixer may fit the bill. If you have a situation that requires more than that then I recommend a non-powered mixer with separate amplifiers. Subgroups-Basicly subgroups allow you to group several inputs onto one fader so you can control them without having to move each individual fader. For example; if you have a band you can group the backup singers to a subgroup, the drums to a subgroup, the guitars to a subgroup and the horn section to another. That way you can adjust the volume of the entire drumset or other group with one fader instead of having to adjust each fader separately. If you have lots of musicians and singers you may want to get a mixer with enough subgroups to handle them. EQ-The last feature to consider is the eq on the mixer. Some smaller mixers will have a main eq section. This will suffice for small, simple setups. Bigger mixers usually don't have main eq sections because they will be used in systems that have outboard eqs. The individual channel strip eqs can vary from a high and low to 4 or 5 frequency selections with sweepable points. I don't want to get too detailed here but if you have a big venue with lots of musicians and someone who knows how to operate a mixer with these features then you need to get a mixer with plenty of onboard eq. Buying a sound system for your church When buying a sound system and AV system for your church there are several factors to consider. We will cover several of them here. Selecting a contractor-This is by far the most important aspect of your Sound and A/V system. There is plenty of  good equipment to be purchased at competitive prices but a good contractor is hard to find. The best way to find a good contractor is by word of mouth. If you have a friend or collegue at another church ask them for a recommendation. You could even call some similar churches in your area and ask them who services thier system. If you have to you can go to the yellow pages. Call several contractors. After you have met with a few get some references and visit some churches where they have installed systems. Talk to the staff at these churches when the contractor is not present and ask them about thier service. Did they install the system in a professional and timely matter? Did they come up with unforseen additional costs? What about training? There is so much more to consider than the price. I often tell prospective customers that we have no interest in being the low bidder because anyone can sell and install a cheap sound system. Make sure that your contractor is a dealer for the equipment they sell. If they are not later service may be difficult. Make sure they have a business liscense and insurance. As a contractor myself I would never do business with a contractor without doing the above steps!!! Budget-Once you have selected a contractor discuss your specific needs with him and ask for a budget. Wait!!! Isn't this backwards? Don't you come up with a budget first and then find a contractor? Well, who in your organiztion knows the cost of intalling a sound A/V system? If you have selected an honest, competent contractor he will work with you to design a system you can afford. Work with him to decide which items are vital and which can be left out or added later if you can't afford them now. Plan for the future-It is important when designing your new system to plan to grow. Hopefully your church will grow in numbers and your worship style may evolve. Plan a system that you can grow into over the next 10 years. For example: If you are using a 12 channel mixer now you may want to get a 16 to 24 channel so you can add inputs later as needed. Don't think your church will always be doing the same things in the future as they are now. Once again your contractor should be able to provide his expertise here. Next month we will cover some more specific items like locations of equipment, power requirements etc.. Buying a sound system for your church When buying a sound system and AV system for your church there are several factors to consider. Last month we covered selecting a contractor, budgeting and planning for the future. This month I am going to cover several items that you need to consider that most architects will not include in their plans. Sound Booth-It is critical to locate your sound booth where the sound operator can hear what the audience hears and can see the performers easily. This can be in the back of the church in an open booth or in the balcony at the front of the balcony. Glassed in rooms or rooms with windows are not acceptable. Power Requirements-It is critical to have the proper power. Any power for the sound system must be on dedicated circiuts. For large installations the power amps should be near the stage. I like to have 1 20 amp circuit for each 2 amplifiers. Another 20 amp circuit is needed for the booth equipment. For video you need power at each projector and at the screen for a powered screen. The projectors and the computer that displays the image need to be on the same circuit. Any TVs or other monitors need a power outlet. See why your contractor needs to involved during the planning stage!! Video-If you are installing video you need to consider several things. The screens need to be placed so the congregation can see them without obstruction. The wall needs to be high enough to fit the screen and baptistry and be over the choir's heads. Also the area from the projector to the screens needs to be free of any obstruction like choir mics or light fixtures. Other Stuff-There are many other things to consider like placement of conduits, speakers, mic jacks and much more. Some buildings need sound treatment to reduce echos. The point is: Get your sound contractor on board during the planning phase. It is imperative that he meet with the architect and view the final plans. Don't leave all this up to your architect. They are not trained to do this. If you are planning to build a church call some contractors today Getting Rid of Feedback It happens to everyone at sometime. Everything if going fine and all of a sudden a loud squeal comes from the speakers. You have just experienced feedback. This article will help identify the causes of and cures for feedback. What is feedback? First of all let's define feedback. Every room and system components have what is called a resonant frequency. That means that as the sounds come out of the speakers most of the frequencies hit the furnishings and people and dissipate. But one or more of these frequencies are matched to the room and instead of dissipating they bounce. When they bounce they re-enter the microphones and are re-amplified over and over again resulting in a single frequency noise called feedback. Since any frequency can feedback this sound can vary from a low pitched moan to a very high pitched squeal. This sound can be in the main speakers or the monitors or both. How do you get rid of it? There are many things you need to do and check to eliminate this problem. Some relate to the physical placement of your equipment and some relate to the electronic setup of your system. First let's tackle physical placement.  Speakers should be in front of the microphones so that the direct sound of the speaker does not enter the mic. Speakers should be aimed so that most of the sound energy is directed at the audience rather than the walls. If you have a very reverberant room you may consider some wall treatments to soak up some of the echoes. Any monitors should be placed so that they aim at the back side of microphones and not into the front. Choir mics and lapel mics are very sensitive and should not be fed into monitors. This is an easy way to cause feedback. Electronically your system should have a good equalizer on the main speakers and on each monitor mix. Use the eq to notch out the problem frequencies. An improperly set eq is a sure way to get feedback. This is a job best left to a pro but one way you can do it yourself is to set your eq flat. Be sure that the channel strip eqs on your mixer are flat too. Then bring your system up until you start to notice a feedback ring. Don't let it get loud but ride the volume to keep it ringing a little. Then push down and bring back up each frequency on your eq one at a time. You should find the one that eliminates the ring. Then bring it back up so that it starts to ring again and then dip it just below that point. There are some eqs on the market that have little lights that tell you which frequency if feeding back. This is a good shortcut. Check your channel strip eqs. If the highs, lows or mids are turned up on any channel this may cause feedback. Set them all flat and start over. Most real pros rarely boost eq but only use cuts to get the sound right. Another tip is to turn off any unused mics. Any mic that is on but not being used is likely to be a trouble maker. Also, when turning on a mic start it a bit low and have your finger on the fader as you turn it on. That way you can correct any problem immediately. I suggest having your system tuned and set up by a pro. They can do this much faster and better. It takes years of experience to set an eq properly. Then follow the rules and you should not have any problems  Different Signal Types And How to interface them into your sound system First lets discuss the different signal types. For this discussion we will only talk about analog signals.There are 3 basic types of analog signals. Balanced -Balanced signals use a positive, a negative and a ground or shield. Balanced signals use connectors with 3 pins or conductors. Usually these are xlr connectors or 1/4" 3 conductor (TRS) phono plugs. Typical balanced signal devices are most microphones, mixers and audio gear with balanced outputs and some instrument amplifiers with balanced outputs. The advantages of a balanced signal are it can be run long distances with only marginal loss and it tends to reject outside noise. Line Level -Line level or unbalanced signals use only a center positive and a shield. Usually they use 1/4" 2 conductor (TS) phono plugs or RCA plugs. Typical line level devices are musical instruments, tape deck and cd players and sound equipment with unbalanced outputs. The disadvantages of line level are it can not be run long distances and tends to pick up outside noise. Speaker Level-Speaker Level is the output of an amplifier that is strong enough to drive speakers. It consists of a positive and negative. OK, so how do you interface these different signals in your sound system. By this I mean if you have a cd player or guitar, how do you plug it into the system. First of all remember that balanced is almost always better than unbalanced. The way to turn unbalanced into balanced is to use a direct box. This box has a transformer inside that changes an unbalanced signal into a balanced signal. When to use one? Anytime you have an unbalanced signal that you need to plug into your sound system from a long distance (25' or more). The direct box has a 1/4" input and an xlr output. This allows you to plug a keyboard, guitar, cd player etc... into a mic jack on your stage. Do not use a cable that just changes the pins. This may result in a weak, noisy signal. Some direct boxes have an attenuator that allows you to even plug a speaker level signal in and change to balanced mic level. This allows you to plug the speaker output of a guitar amp right into a mic jack. Be sure to engage the attenuator first!!! Rolls makes a special direct box called a DB-14 Director that allows you to plug a CD or tape deck in and control the left and right volume level. This allows you to use a CD player from the stage and control the volume of a split track. This is very handy for choir rehersal. Being Prepared   I do a lot of training for church sound system operators. The first thing I tell the trainees is no matter how good an operator you are or how good the system is, if you do not come in early and prepare for the event you will not suceed. The most important thing to a sucessful event is preparation and communication. I had a customer recently who had an Easter program at his church. No one involved with the program consulted with him about the sound requirements and it was a disaster. This happens quite often. Sound guys, the reality is most of the people who put together programs don't even give the sound requirements a second thought. That makes it our responsiblity to go to them and find out what they need. If you do this consistently many of them will start to consult with you when they are putting thier programs together. Especially when they see how much better the program goes when the sound is right. These are a few things to check before any service. 1. Check batteries in wireless. If in doubt, change them. You don't want to ruin a service for $2.00 worth of batteries. 2. Check all mics to be used. Don't assume they all work. You never know what got changed or moved during the week. 3. Check monitors and be sure they work 4. Do a quick sound check with any soloists 5. Get all your recording media ready 6. One a month check the speakers for blown drivers. If you show up early and make sure everything is ready you are sure to have a trouble free service.     Feature Article     70 Volt systems   I only got one question last month so this month I am going to talk about 70 volt sound systems. 70 Volt systems are used when you need to run a lot of speakers on one amplifier or there is a long distance between the amplifier and the speakers. Typical uses would be: Hallways, entrances, offices and classrooms in a church or school; large retail spaces like malls or grocery stores; large outdoor areas like theme parks.   The reason you use a 70 volt system is because if you tried to string a bunch of 8 ohm speakers on a standard amplifier you would quickly show an almost zero resistance load to the amplifier resulting in overheating and premature failure. A 70 volt amplifier has a large transformer inside which steps up the voltage and steps down the current (see ohms law: P=V2/R). Then each speaker along the line has a small transformer which steps down the voltage and steps the current back up. This allows you to string numerous speakers in parallel and run the speaker lines long distances.   It is important yet very simple to determine the correct size amplifier in a 70 volt system. You simply add up the wattage of the speakers and get an amplifier at least that size or bigger. For example: If you are going to use 10 speakers with 10 watt taps then use at least a 100 watt amplifier. Of course it must be a 70 volt amp. I like to use an amp a little bigger in case you want to add more speakers later.   Using 70 volt systems are a very efficient way to distribute sound to lots of areas but they are not generally recommended for projecting sound to a large audience like a church service or concert. The reason is that 70 volt systems are limited in power due to the limits of the transformers and suffer from some loss of fidelity, particularly in the low frequencies since transformers do not pass these well.   Please call or e-mail with any questions.     Feature Article     Using Crossovers and Subwoofers   People come in my shop all the time who do not understand the function of crossovers or how to hook them up so let's address that this month. Function-The function of a crossover is to separate different frequency ranges and sent them to the appropriate device. This can be as simple as a passive 2 way crossover in speaker cabinet or a 4 way active crossover in a large sound system. The small passive crossover may send frequencies from 500 hz and down to the woofer and everything from 500hz and up to the horn (The frequency will vary from speaker to speaker according to the design). This serves several functions. First of all; horns are designed to reproduce highs and woofers are designed to reproduce lows so using a crossover  allows each component to work more efficiently. Also, sending low frequencies to the horn will damage it. An active crossover is a device separate from the speakers that is placed in the signal path last in line before the amplifiers. An active crossover will allow you to set crossover points yourself and adjust the gain of different frequency ranges. How to-There are numerous ways to set up and use a crossover. For the purpose of this article I am going to cover three ways to use a crossover to hook up subwoofers. 1. Left and Right Main to Stereo two way crossover. Take the main left and right out to your eq or other processing. The last in the chain before the amps should be your crossover. This will send your mid/highs to your top speakers and your lows to your subs. See Fig. 1 2. Main Out and Aux Send-This is a good way IF you are an experienced sound guy and know what you are doing. By sending an aux send to the subwoofer you get ultimate control over what gets sent to the subwoofer. See Fig. 2 3. Subs with built in crossover-This method utilizes the crossover built into a subwoofer. (Some have this feature). This separates the lows/highs at the subwoofer. This is my least favorite way because you lose all control of the crossover points and the gain and you have to have a really big amp. See Fig 3 There are many more ways to do it but these are basic popular ways. Experiment and find what's best for you.