How to Remove Audio Feedback through Equalization

By Chris Huff

Not all feedback is eliminated in the same way. Feedback typically occurs when a microphone and a loudspeaker are too close together thanks to a singer dropping the mic to their side. In this case, let's call it user error. But have you ever had multiple people use the same microphone and suddenly you hear the ringing of feedback? Have you ever created feedback by altering the EQ of a channel? Let's find out why.

What is feedback?

Audio feedback is the sound created when a sound loops between an audio input and an audio output. A simple example is a microphone and a monitor. The monitor is broadcasting sound the microphone then picks up. The monitor then is amplifying that sound and broadcasting it back out where the microphone picks it up again. Eventually, when the volume going into the microphone is the same as the volume coming out of the monitor, feedback begins.

The first frequency that feeds back is the one that requires the least amount of energy to excite resonance. Resonance is a vibration of large amplitude caused by a relatively small stimulus of the same or nearly the same period as the natural vibration period of the system.

What are the common reasons for audio feedback?

  1. Microphone located too close to a monitor
  2. Gain structure set too high so as frequencies primed for feedback

What can be done to stop audio feedback in these cases?

  • Move the microphone
  • Move the monitor
  • Use a more directional microphone to meet your mic'ing need.
  • Turn down the monitor volume
  • Turn down microphone gain (likely the person needs to hold the mic to their lips if singing)
  • Watch for reflective surfaces that might be bouncing the monitor sound to a microphone not directly in line with the monitor. Then, make changes then using one of the above.
  • Simple but common...turn off microphones when not in use. A stage arrangement can change for an event and create the right conditions for an open mic to cause feedback.
  • Equalize the microphone channel signal, lowering the frequencies which are causing the feedback.

How does the equalization-for-feedback process work?

In the first part of the article, I mentioned the frequency that required the least amount of energy to excite resonance. Let's lasso that one to the ground!

Frequencies by their sound:

  • Hoots and howls: Likely caused by a feedback frequency in the 250 to 500 Hz range.
  • Singing: The range is in-line with 1kHz.
  • Whistles and screeches: most likely above 2 kHz.

Determine the likely frequency range and then apply a cut to that range by 3dB.

What about creating feedback when EQ'ing a channel?

It's that very EQ process where we can cause feedback ourselves. For example, one time I had choir mic's all set and EQ'ed to my liking. During a specific song, I decided to try boosting the mid-range EQ a bit more (that 1kHz range). That's when the feedback started. I quickly cut that mid-range frequency back before anyone (except my sound guy, Jeff) noticed.

The keys to feedback control

Eliminate the conditions in which it can appear. Teach singers to hold the mic right up to their lips...and never drop down next to a monitor, establish proper gain structure, and turn off unused mic's.

When it does appear, know that you have an immediate alternative to turning down might just be able to EQ it out.

Question(s): What have you done to control feedback in your environment?

By Chris Huff, of Used by permission.

Free Book: A Tale of Two Mixers

There has been a whole lot of hubbub about several new, smaller digital mixers.

Sorry. All gone, now.
A very short book has been written comparing features on the most popular among them: to sort through the hubbub, and examine them in light of the real world. Part tongue-in-cheek, part real-world review, part spec comparison, it's a useful tool. And hey, it's FREE!

David McLain, CTS | Technical Sales CCI  SOLUTIONS
Be seen. Be heard.
PO Box 481 / 1247 85th Ave SE
Olympia, WA  98507-0481
Voice: 800/426-8664 x2155 / Fax: 360/754-1566
personal email:
CCI Solutions online:
Church Soundguy blog:

Fitting a Countryman E6 Mic

The Countryman E6 and E6i mics are among the most popular mics in the world today. But fitting them is a little tricky. Here's how it works best.

When Old Becomes New: Hearing Loop Assisted Listening Systems

As more of our nation is diagnosed with hearing loss, it's important that we offer our parishioners the best assisted listening options possible.

It’s always interesting to see old technology become new again.

We see it daily in our lives, but I’m referring to a specific type of old tech; hearing loops.

The technology, which is correctly known by the name of inductive loops, has been in existence for decades.

Based on Faraday’s law of induction, a magnetic field is created and individuals that have a Telecoil (t-coil) equipped hearing aid, can receive audio signals directly in their hearing aid.

A “loop” is a relatively low-tech solution. In simple terms an area is surrounded “looped” with a piece of copper wire.

An amplifier drives signal down that wire creating a magnetic field inside the “loop”.

To receive the magnetic signal a person inside of the field simply has to switch their hearing aid to the “T” (t-coil) position.

With the current ADA (American Disabilities Act) requirements and an aging population, providing a loop based hearing assistance system can be beneficial not only for compliance but also for the convenience of our parishioners.

“Hearing loss is a significant issue. As the baby boomers come of age, the years of industrial sounds and/or noise pollution coupled with exposure to loud music has accelerated the problem,” says Todd Billin of Hearing Loop Systems.

With 36 million of Americans reporting hearing loss and over 8 million already outfitted with hearing aids, the need for hearing loops continues to grow.

There has been no stronger advocate than David G. Myers, PhD, Professor and Social Psychologist at Hope College.

When visiting Europe and attending a service at an old cathedral, Dr. Myers noticed a sign on the wall and remembered the words of the audiologist he purchased the hearing aids.

He knows upon seeing the “Hearing Loop Installed” sign that if he flipped a switch on his hearing aid he’d be tapping directly into the house audio.

Sure enough, from the moment Dr. Myers flipped that switch he has been and continues to be a huge supporter of the technology.

He is the creator of, a website that provides education and information on hearing loops.

“I activate my T-Coils and instantly the speaker’s voice comes to me not from some distant loudspeaker but seemingly from the center of my head, says Myers.

“My hearing aids now serve me as customized wireless loudspeakers”

There can, of course, be challenges when installing a loop system.

The most obvious being how to route the cable in an existing space.

“In all of the existing buildings in which I have designed and installed loops, including very old churches, airport terminals and sporting venues, like the Michigan State Breslin Center, I have always found somewhere to hide the wire for the loop system,” says Tim Vander Meer of Hearing Loop systems.

A loop can cause a high pitched noise through some instruments pickups such as guitar, piano, strings.

Generally speaking this usually happens on older pickups or installations where there is not a solid ground present.

Spillover into adjacent rooms can also be an issue; this also can be overcome by using a properly designed phased array system.

The advantage of a loop is that there is no need for portable receivers and batteries as the t-coil in the hearing aid requires no power.

Additionally the hygiene issue goes away as earphones do not need to be cleaned and shared.

However, for those individuals not using t-coil equipped hearing aids, portable receivers are still, of course, available.

There is also a cost/benefit savings compared to traditional RF and Infrared systems, as the only limit on users of loop systems is physically how many people can fit inside of a loop.

As you consider assisted listening systems for parishioners in the future, whether for compliance or convenience, I would certainly consider a loop system.

What are your thoughts on assisted listening systems? Let me know in the comments below!

Gary Zandstra is a professional AV systems integrator with Parkway Electric and has been involved with sound at his church for more than 25 years.

From ProSoundWeb, used with permission.

Channel Inserts

The Signal Route
The Ins and Outs of Channel Inserts

One of the features often found on the rear panel of a mixing console is the Channel Insert. The insert serves simultaneously as both an input and an output for either a single channel or for some other signal path, such as a submix or main output bus. It is a point in the signal path at which the signal can be detoured — sent out of the mixer — and then returned to its normally scheduled programming, creating what is called an effects loop. In other words, it allows you to “insert” an outboard device into the signal path. On most mixers, a single ¼” three-conductor jack provides connections for both an input and an output.

What would you do with such a strange jack?
1. Apply effects to a channel or submix. Because an insert is both an input and an output, you can route the signal from the channel out to a reverb, compressor, limiter, etc., and then back into the channel. You might send the signal to a noise gate to automatically “turn off” a mic when it's not in use. Reducing the number of mics that are on, or “open”, reduces the risk of feedback and improves your signal-to-noise ratio.

2. Use it as a direct output, like a post-mic preamp, but pre low-cut filter, mute, EQ, fader, etc. Just because you're sending something out doesn't mean you have to bring it back. You can use each insert to send a “direct out” signal to a line-level input of a tape recorder, or to another mixer for a broadcast or recording feed. At the mixer end of your direct out cable, you'll want a standard 1/4" mono (or TS, tip/sleeve) phone plug. Push the phone plug part way into the insert jack, just to the first click. This will route the direct out signal via the cable, without interrupting the signal flow in the mixer. If you insert the plug all the way to the second click, you will still get a direct out signal, but the signal in the channel will be interrupted at that point — removed from the mix.

3. Insert a signal through a “Y” cable — using the insert as both a direct out and an effects loop. As an alternate approach, create your effects loop as described earlier, then insert a “Y” adapter after the processor to affect (compress, for example) both the direct out and the individual channel in the mix. A good application for this might be to compress a pastor’s lapel mic or a pulpit mic, in both the house mix and a recording or broadcast.

Whether you use them as part of your normal setup every week, or just to solve an occasional routing problem, inserts add tremendously to the versatility of your mixing console.

Information provided by kind permission, Mackie Designs, Woodinville, Washington. Reprinted from Mackie Church Sound Notebook

Sound System Interconnection

Or: Dealing With Ground Loop Hums
Rane Technical Staff
RaneNote 110 written 1985; last revised 12/2009


This note, originally written in 1985, continues to be one of our most useful references. Its popularity stems from the continual and perpetual difficulty of hooking up audio equipment without suffering through all sorts of bizarre noises, hums, buzzes, whistles, etc.-- not to mention the extreme financial, physical and psychological price. As technology progresses it is inevitable that electronic equipment and its wiring should be subject to constant improvement. Many things have improved in the audio industry since 1985, but unfortunately wiring isn't one of them. However, finally the Audio Engineering Society (AES) has issued a standards document for interconnection of pro audio equipment. It is AES48, titled "AES48-2005: AES standard on interconnections -- Grounding and EMC practices -- Shields of connectors in audio equipment containing active circuitry."

Rane's policy is to accommodate rather than dictate. However, this document contains suggestions for external wiring changes that should ideally only be implemented by trained technical personnel. Safety regulations require that all original grounding means provided from the factory be left intact for safe operation. No guarantee of responsibility for incidental or consequential damages can be provided. (In other words, don't modify cables, or try your own version of grounding unless you really understand exactly what type of output and input you have to connect.)

Ground Loops

Almost all cases of noise can be traced directly to ground loops, grounding or lack thereof. It is important to understand the mechanism that causes grounding noise in order to effectively eliminate it. Each component of a sound system produces its own ground internally. This ground is usually called the audio signal ground. Connecting devices together with the interconnecting cables can tie the signal grounds of the two units together in one place through the conductors in the cable. Ground loops occur when the grounds of the two units are also tied together in another place: via the third wire in the line cord, by tying the metal chassis together through the rack rails, etc. These situations create a circuit through which current may flow in a closed "loop" from one unit's ground out to a second unit and back to the first. It is not simply the presence of this current that creates the hum -- it is when this current flows through a unit's audio signal ground that creates the hum. In fact, even without a ground loop, a little noise current always flows through every interconnecting cable (i.e., it is impossible to eliminate these currents entirely). The mere presence of this ground loop current is no cause for alarm if your system uses properly implemented and completely balanced interconnects, which are excellent at rejecting ground loop and other noise currents. Balanced interconnect was developed to be immune to these noise currents, which can never be entirely eliminated. What makes a ground loop current annoying is when the audio signal is affected. Unfortunately, many manufacturers of balanced audio equipment design the internal grounding system improperly, thus creating balanced equipment that is not immune to the cabling's noise currents. This is one reason for the bad reputation sometimes given to balanced interconnect.

A second reason for balanced interconnect's bad reputation comes from those who think connecting unbalanced equipment into "superior" balanced equipment should improve things. Sorry. Balanced interconnect is not compatible with unbalanced. The small physical nature and short cable runs of completely unbalanced systems (home audio) also contain these ground loop noise currents. However, the currents in unbalanced systems never get large enough to affect the audio to the point where it is a nuisance. Mixing balanced and unbalanced equipment, however, is an entirely different story, since balanced and unbalanced interconnect are truly not compatible. The rest of this note shows several recommended implementations for all of these interconnection schemes.

The potential or voltage which pushes these noise currents through the circuit is developed between the independent grounds of the two or more units in the system. The impedance of this circuit is low, and even though the voltage is low, the current is high, thanks to Mr. Ohm, without whose help we wouldn't have these problems. It would take a very high resolution ohm meter to measure the impedance of the steel chassis or the rack rails. We're talking thousandths of an ohm. So trying to measure this stuff won't necessarily help you. We just thought we'd warn you.

The Absolute Best Right Way To Do It

The method specified by AES48 is to use balanced lines and tie the cable shield to the metal chassis (right where it enters the chassis) at both ends of the cable.

Figure 1a. The right way to do it.

Figure 1b. Recommmended practice.

A balanced line requires three separate conductors, two of which are signal (+ and -) and one shield (see Figure 1a). The shield serves to guard the sensitive audio lines from interference. Only by using balanced line interconnects can you guarantee (yes, guarantee) hum-free results. Always use twisted pair cable. Chassis tying the shield at each end also guarantees the best possible protection from RFI [radio frequency interference] and other noises [neon signs, lighting dimmers].

Neil Muncy, an electroacoustic consultant and seasoned veteran of years of successful system design, chairs the AES Standards Committee (SC-05-05) working on this subject. He tirelessly tours the world giving seminars and dispensing information on how to successfully hook-up pro audio equipment2. He makes the simple point that it is absurd that you cannot go out and buy pro audio equipment from several different manufacturers, buy standard off-the-shelf cable assemblies, come home, hook it all up and have it work hum and noise free. Plug and play. Sadly, almost never is this the case, despite the science and rules of noise-free interconnect known and documented for over 60 years (see References for complete information).

It all boils down to using balanced lines, only balanced lines, and nothing but balanced lines. This is why they were developed. Further, that you tie the shield to the chassis, at the point it enters the chassis, and at both ends of the cable (more on `both ends' later).

Since standard XLR cables come with their shields tied to pin 1 at each end (the shells are not tied, nor need be), this means equipment using 3-pin, XLR-type connectors must tie pin 1 to the chassis (usually called chassis ground) -- not the audio signal ground as is most common.

Not using signal ground is the most radical departure from common pro-audio practice. Not that there is any argument about its validity. There isn't. This is the right way to do it. So why doesn't audio equipment come wired this way? Well, some does, and since 1993, more of it does. That's when Rane started manufacturing some of its products with balanced inputs and outputs tying pin 1 to chassis. So why doesn't everyone do it this way? Because life is messy, some things are hard to change, and there will always be equipment in use that was made before proper grounding practices were in effect.

Unbalanced equipment is another problem: it is everwhere, easily available and inexpensive. All those RCA and 1/4" TS (Tip-Sleeve) connectors found on consumer equipment; effect-loops and insert-points on consoles; signal processing boxes; semi-pro digital and analog tape recorders; computer cards; mixing consoles; et cetera.

The next several pages give tips on how to successfully address hooking up unbalanced equipment. Unbalanced equipment when "blindly" connected with fully balanced units starts a pattern of hum and undesirable operation, requiring extra measures to correct the situation.

The Next Best Right Way To Do It

The quickest, quietest and most foolproof method to connect balanced and unbalanced is to transformer isolate all unbalanced connections. See Figure 2.

Figure 2. Transformer Isolation

Many manufacturers provide several tools for this task, including Rane. Consult your audio dealer to explore the options available.

The goal of these adapters is to allow the use of standard cables. With these transformer isolation boxes, modification of cable assemblies is unnecessary. Virtually any two pieces of audio equipment can be successfully interfaced without risk of unwanted hum and noise.

Another way to create the necessary isolation is to use a direct box. Originally named for its use to convert the high impedance, high level output of an electric guitar to the low impedance, low level input of a recording console, it allowed the player to plug "directly" into the console. Now this term is commonly used to describe any box used to convert unbalanced lines to balanced lines.

The Last Best Right Way To Do It

If transformer isolation is not an option, special cable assemblies are a last resort. The key here is to prevent the shield currents from flowing into a unit whose grounding scheme creates ground loops (hum) in the audio path (i.e., most audio equipment).

It is true that connecting both ends of the shield is theoretically the best way to interconnect equipment -- though this assumes the interconnected equipment is internally grounded properly. Since most equipment is not internally grounded properly, connecting both ends of the shield is not often practiced, since doing so usually creates noisy interconnections.

A common solution to these noisy hum and buzz problems involves disconnecting one end of the shield, even though one can not buy off-the-shelf cables with the shield disconnected at one end. The best end to disconnect is the receiving end. If one end of the shield is disconnected, the noisy hum current stops flowing and away goes the hum -- but only at low frequencies. A ground-sending-end-only shield connection minimizes the possibility of high frequency (radio) interference since it prevents the shield from acting as an antenna to the next input. Many reduce this potential RF interference by providing an RF path through a small capacitor (0.1 or 0.01 microfarad ceramic disc) connected from the lifted end of the shield to the chassis. (This is referred to as the "hybrid shield termination" where the sending end is bonded to the chassis and the receiving end is capacitively coupled. See Neutrik's EMC-XLR for example.) The fact that many modern day installers still follow this one-end-only rule with consistent success indicates this and other acceptable solutions to RF issues exist, though the increasing use of digital and wireless technology greatly increases the possibility of future RF problems.

If you've truly isolated your hum problem to a specific unit, chances are, even though the documentation indicates proper chassis grounded shields, the suspect unit is not internally grounded properly. Here is where special test cable assemblies, shown in Figure 3, really come in handy. These assemblies allow you to connect the shield to chassis ground at the point of entry, or to pin 1, or to lift one end of the shield. The task becomes more difficult when the unit you've isolated has multiple inputs and outputs. On a suspect unit with multiple cables, try various configurations on each connection to find out if special cable assemblies are needed at more than one point.

Figure 3. Test cable

See Figure 4 for suggested cable assemblies for your particular interconnection needs. Find the appropriate output configuration (down the left side) and then match this with the correct input configuration (across the top of the page.) Then refer to the following wiring diagrams.

Figure 4. Interconnect chart for locating correct cable assemblies.

Note: (A) This configuration uses a standard "off-the-shelf" cable.

Note: (B) This configuration causes a 6 dB signal loss. Compensate by "turning the system up" 6 dB.

Ground Lifts

Many units come equipped with ground lift switches. In only a few cases can it be shown that a ground lift switch improves ground related noise. (Has a ground lift switch ever really worked for you?) In reality, the presence of a ground lift switch greatly reduces a unit's ability to be "properly" grounded and therefore immune to ground loop hums and buzzes. Ground lifts are simply another Band-Aid to try in case of grounding problems. It is, however, true that an entire system of properly grounded equipment, without ground lift switches, is guaranteed (yes guaranteed) to be hum free. The problem is most equipment is not (both internally and externally, AC system wise) grounded properly.

Most units with ground lifts are shipped so the unit is "grounded" -- meaning the chassis is connected to audio signal ground. (This should be the best and is the "safest" position for a ground lift switch.) If after hooking up your system it exhibits excessive hum or buzzing, there is an incompatibility somewhere in the system's grounding configuration. In addition to these special cable assemblies that may help, here are some more things to try:

  1. Try combinations of lifting grounds on units supplied with lift switches (or links). It is wise to do this with the power off!
  2. If you have an entirely balanced system, verify all chassis are tied to a good earth ground, for safety's sake and hum protection. Completely unbalanced systems never earth ground anything (except cable TV, often a ground loop source). If you have a mixed balanced and unbalanced system, do yourself a favor and use isolation transformers or, if you can't do that, try the special cable assemblies described here and expect it to take many hours to get things quiet. May The Force be with you.
  3. Balanced units with outboard power supplies (wall warts or "bumps" in the line cord) do not ground the chassis through the line cord. Make sure such units are solidly grounded by tying the chassis to an earth ground using a star washer for a reliable contact. (Rane always provides this chassis point as an external screw with a toothed washer.) Any device with a 3-prong AC plug, such as an amplifier, may serve as an earth ground point. Rack rails may or may not serve this purpose depending on screw locations and paint jobs.

Floating, Pseudo, and Quasi-Balancing

During inspection, you may run across a 1/4" output called floating unbalanced, sometimes also called psuedo-balanced or quasi-balanced. In this configuration, the sleeve of the output stage is not connected inside the unit and the ring is connected (usually through a small resistor) to the audio signal ground. This allows the tip and ring to "appear" as an equal impedance, not-quite balanced output stage, even though the output circuitry is unbalanced.

Floating unbalanced often works to drive either a balanced or unbalanced input, depending if a TS or TRS standard cable is plugged into it. When it hums, a special cable is required. See drawings #11 and #12, and do not make the cross-coupled modification of tying the ring and sleeve together.


If you are unable to do things correctly (i.e. use fully balanced wiring with shields tied to the chassis at the point of entry, or transformer isolate all unbalanced signals from balanced signals) then there is no guarantee that a hum free interconnect can be achieved, nor is there a definite scheme that will assure noise free operation in all configurations.

Winning the Wiring Wars

  • Use balanced connections whenever possible, with the shield bonded to the metal chassis at both ends.
  • Transformer isolate all unbalanced connections from balanced connections.
  • Use special cable assemblies when unbalanced lines cannot be transformer isolated.
  • Any unbalanced cable must be kept under ten feet (three meters) in length. Lengths longer than this will amplify all the nasty side effects of unbalanced circuitry's ground loops.
  • When all else fails, digitize everything, use fiber optic cable and enter a whole new realm of problems.


  1. Neil A. Muncy, "Noise Susceptibility in Analog and Digital Signal Processing Systems," presented at the 97th AES Convention of Audio Engineering Society in San Francisco, CA, Nov. 1994.
  2. Grounding, Shielding, and Interconnections in Analog & Digital Signal Processing Systems: Understanding the Basics; Workshops designed and presented by Neil Muncy and Cal Perkins, at the 97th AES Convention of Audio Engineering Society in San Francisco, CA, Nov. 1994.
  3. The entire June 1995 AES Journal, Vol. 43, No. 6, available $6 members, $11 nonmembers from the Audio Engineering Society, 60 E. 42nd St., New York, NY, 10165-2520.
  4. Phillip Giddings, Audio System Design and Installation (SAMS, Indiana, 1990).
  5. Ralph Morrison, Noise and Other Interfering Signals (Wiley, New York, 1992).
  6. Henry W. Ott, Noise Reduction Techniques in Electronic Systems, 2nd Edition (Wiley, New York, 1988).
  7. Cal Perkins, "Measurement Techniques for Debugging Electronic Systems and Their Instrumentation," The Proceedings of the 11th International AES Conference: Audio Test & Measurement, Portland, OR, May 1992, pp. 82-92 (Audio Engineering Society, New York, 1992).
  8. Macatee, RaneNote "Grounding and Shielding Audio Devices," Rane Corporation, 1994.
  9. Philip Giddings, "Grounding and Shielding for Sound and Video," S&VC, Sept. 20th, 1995.
  10. AES48-2005: AES standard on interconnections "Grounding and EMC practices -- Shields of connectors in audio equipment containing active circuitry" (Audio Engineering Society, New York, 2005).

Band-Aid is a registered trademark of Johnson & Johnson

Note: this is not basic Sound Guy instruction: these are advanced tools. In other words, don't modify cables, or try your own version of grounding unless you really understand exactly what type of output and input you have to connect.

Copyright Rane Corporation. Used by permission.

This document is also available as a pdf document.

Note: A version of this RaneNote was published in the Journal of the Audio Engineering Society, Vol. 43, No. 6, June, 1995.

Install Your Own Church Sound System? Here Are Some Cautionary Tales

While installing a sound system isn't exactly rocket science, it is more complex than painting one's house. That's one reason why you need to do your homework

September 10, 2010, by Curt Taipale
church sound installation
Audio consultants often find themselves working with people in churches who seem eternally bent on saving money at any cost. This is the kind of church that will call with the seemingly innocent request to have the consultant design a new sound system for them. At some point in the conversation they’ll add that they want to do the installation themselves.
That approach can be a mixed blessing both for the consultant and for the church. On the one hand, at least they’re using a consultant’s seasoned advice to make the best choices of gear for them to use. The problem starts when they begin to think that the process of actually installing the gear isn’t all that difficult.
Momentary Lapses of Intelligence
Here are some textbook cases. In order to protect the innocent, I’ll use their real names.
So one day my friend Warren calls me and announces that his church is ready to renovate their existing sound system, and they want to do it right this time. He invites me to meet with their sound committee, and within a few days I’ve got the project to design the system.
In order to save money, the church plans to use volunteers to run all the wire, hang the loudspeakers, and wire up the sound booth gear. I insisted on wiring up the amplifier rack myself, to be a friend, save them the work, and me the headache of possibly having to fix it later.
A couple of months later the equipment is all sitting at the church, and the troops are ready to proceed with the install. So I arrive with TEF and solder station in hand ready to talk them through the install.
Now right off the bat, I’m scared by what I see. To free myself from any liability in the future, I do what every good consultant does - I don’t give them any advice at all about how to hang the loudspeakers in a safe manner. That’s really the job of the sound contractor.
They assure me that they’ve researched their hanging method carefully, and at my insistence have even had a structural engineer sign off on their solution, but I make a mental note to not find myself standing under the cluster for any length of time.
After a lot of scraped knuckles, sweat, grunts and groans, the loudspeaker wire, microphone snakes and return lines are finally pulled into place. At around 1 am on the third day of the installation, we finally light up the system and start to voice it.
By this time, everyone is toast. I’m so tired I can hardly see straight, let alone hear really well. The volunteer crew is absolutely wiped out, but we’re so close now that they’re not about to leave without hearing the system lit up for the first time, so they’re napping on the pews while I continue to work.
To their credit, there were no polarity reversals anywhere in the system. Bless God, somebody was paying attention.
Don’t get me wrong. The church loves their new sound system. And I’m sure the crew has good memories of the time they invested on that project.
But by the end of the project everyone was wiped out, stressed out, on the verge of being mad at everyone, and just plain in a bad mood.
More Angst
I recently finished another project like this. My friend Duane had his best “ain’t no way on earth that’ll happen” look on his face when he considered the idea of using a sound contractor to do their installation.
So I designed the system, gave them a shopping list, and answered a myriad of questions as the project went from a few pieces of paper to loudspeakers hanging somewhat precariously from the steel.
Here again, the weakness seems to come in not knowing precisely how to safely hang really heavy loudspeakers over people’s heads. Hanging heavy loudspeakers isn’t easy in the first place. Getting them aimed precisely where they need to be aimed is an additional challenge.
But when I saw the loudspeakers hanging from S-hooks and swing-set chain, I knew they had ignored my urging to buy their hardware from a professional rigging supplier. They didn’t have a smile on their face when I insisted that they replace the chain and hardware with the real stuff. And don’t even get me started on the points they wanted to hang the boxes from.
Part of the angst of Duane’s project came through the scheduling. All involved wanted the system to be in place in time for their Easter pageant. Flying the loudspeakers meant having to move scaffolding into the room in order to pull wire and hang loudspeakers.
During the same time frame, the drama and music team needed access to the stage for their pageant rehearsals several evenings each week, so having scaffolding on the stage was a problem. Just try sharing a stage with those two groups.
The installers had to remove the scaffolding and all of their stuff each evening so that the pageant rehearsals could continue as scheduled. That process added undue pressure on the volunteer sound installers.
You wouldn’t make the same mistake?! I’m sure that’s what Duane felt. Happened anyway. Nobody lost their salvation over it, but it’s certainly something they wouldn’t do on purpose again.
Before I continue, please understand. The guys that find themselves in these predicaments aren’t dolts. They’re bright, sharp, astute, focused, detail-type personalities.
But by the time they realize that they’re in over their heads, it’s too late to drop back and do anything else about it. They’ve got to see it through and get on with life.
So what makes such a rational, educated person think that they can install a sound system just as well as a seasoned sound contractor? Contractors have years of hard-won experience they can draw upon every time they hang a loudspeaker or wire up a rack.
As well meaning as they are, churches who set out to do this work on their own are in no better position than that sound contractor on his very first install.
I talked recently with my new friend, Rod, who was just then receiving the equipment that I specified and he ordered. His conversation with me then was filled with the usual confidence that both Duane and Warren shared in their first dialogs with me.
Rod was certain that he could have the cluster in the air and ready to get sound out of it within the next couple of weeks. I tried my best to cool his optimism while still being encouraging. I knew that if his experience was anything like most of the others, he’d be in for a real surprise!
Well, I just spent this past weekend commissioning the sound system that I designed and that Rod and friends installed. I called him last Thursday night before I left to make sure that he was really, truly ready for me to be there, and he assured me that all would be fine.
When I arrived in his town, I called again and his response was, “Well, we’ll be ready, but don’t hurry over here.” As I walked into the church, he had just finished making the final connections in the amp rack. To their credit, our system voicing process wasn’t delayed.
Rod finally realized - just like Warren, and Duane, and others have - that installing a sound system properly isn’t as simple or as easy as many want to think early on in the process.
Yeah, But ...
Look, I know your church is different. I know y’all won’t make the same mistakes that most other churches make during this process. And I know your church will end up with an award-winning sound system that will make every sound contractor green with envy.
But just humor me. Tell me you’re at least going to consider hiring a first rate sound contractor for your next system installation. It’ll make me feel better.
For what it’s worth, I also know that there are some contractors out there who shouldn’t be in business. Frankly, you probably could do the work better than some sound contractors out there.
Even though we’re not professional painters, I think that my wife and I do a more careful job of painting our house simply because it’s our house - we live there every day and care about it more than your typical painting contractor would.
But as much as I know about electricity and electronics, I’m not going to volunteer to wire our next house. I might do some extra stuff - like putting lights in the closets, adding phone outlets in all of the rooms, and so on. But I’m not interested in doing the entire job myself.
While installing a sound system isn’t exactly rocket science, it is more complex than painting one’s house. That’s one reason why you need to do your homework on the contractors you’re considering.
Please at least seriously think through all of the realities before you let your church go off the deep end in their eagerness to simply save some money. They may save a few dollars during the installation, but the toll that the process exacts from the church’s volunteers may not be worth it in the long run.
People are more important than money. And it may be that later on y’all will find yourselves doing the work all over again.
A Quiet Voice of Reason
Now, don’t go around telling everyone that Curt said that no church should install their own sound system. I didn’t say that. All I hope to offer here is a voice of reason in your eager pursuit to save a couple of bucks.
If you’re thinking about installing your own sound system, please determine now that you will sort through every possible issue. Develop a contingency plan for all of the things that are going to go differently than you plan, because they will. Step back and think it through before your eagerness gets the best of you.
For example, what are you going to do when the input panels for the floor pockets don’t come in with the connectors laid out the way you told them to? What are you going to do when you discover - after the scaffolding and scissor lift are long gone - that you hung the cluster two feet higher than it should have been?
What are you going to do when the mic snake you ordered arrives with totally the wrong connectors? What are you going to do when your consultant discovers through his acoustical testing that two of your four main loudspeakers have their woofers wired out of polarity - that they came that way from the loudspeaker manufacturer!?!
No, really. Tell me what you’re going to do. Because if you’re installing the sound system yourself, you ARE the sound contractor. It’s your job to make sure the installation and every device in the project is working correctly and installed properly.
And if you’re like most churches, you’re not only installing the sound system, you’re also installing the video system, and the stage lighting system, and… The size of the task can mushroom beyond your wildest expectations in no time.
I assume you’ll be trying to accomplish this task while gainfully employed in another job, so your installation efforts will be done in the evenings and on weekends. You’ll probably need to take vacation time during the last few days of the project when everything comes together.
And I assume that, if you can find volunteers as eager to help you as you are to take on this project, that they too will be there whenever they can. Be prepared to discover that their available times might not be the same times as you plan to work, or nearly as often.
Do your best to step away from the project long enough to see the big picture and what the process is going to do to you, to your life, to your family, to your friends who are going to help you get this job done, and to your church.
The church as a whole has enough people who have been burned out or hurt emotionally through their service to their local church. We don’t need to add any new people to that list.
Uncle, Uncle
Okay, I’ve beat you up enough. If after all of this you’re still convinced that you need to do the install yourself, get prayed up and go for it. As long as you know up front that it’s not as easy as you think it will be.
The reality is that there can be tremendous value to having church staff and/or volunteers install their own sound system. More important than the money you’ll save is the fact that they’ll emotionally take ownership of the system more quickly.
Also, if anything ever goes wrong with the system - and we both know that will be discovered on Sunday morning before the service - your volunteers will know where every piece of equipment and scrap of wire is in the entire facility, and how it’s hooked up.
They may even be able to track down the problem and fix it before the service instead of sometime later next week when the sound contractor’s audio technician can schedule an appointment. That works of course until the folks that did the install get relocated by their job, or move to another church for some reason.
Remember that, whatever happens, God is still on the throne. So have fun. Or else.
Curt Taipale heads up Church Soundcheck, a thriving community dedicated to helping technical worship personnel. Courtesy ProSoundWeb; used by permission. 

Shure's Summary of the 2010 White Spaces Order

Copyright 2010 Shure Incorporated
On September 23, 2010, the FCC issued a Second Memorandum Opinion and Order finalizing rules that make the “white spaces” in the TV bands – unoccupied channels between over-the-air TV stations – available for use by unlicensed broadband wireless devices such as next-generation smartphones, computers, and other consumer and commercial products. The 2010 Order mandates the operating rules and technical specifications for both Fixed and Portable TV Band devices, and finalizes some legal and technical issues that remained unresolved since the previous November 2008 Order.
Wireless Microphones Remain Legal Throughout TV Bands
The White Spaces Order does not alter the ability of wireless microphones, in-ear monitors, intercom systems, and related equipment to operate in the TV bands. Wireless microphone users may continue to operate, with or without a license, on any VHF or UHF TV channel (2-51, except 37) that is not assigned to a local TV station or Public Safety agency.
Avoiding Interference In The Future
The 2010 Order establishes a set of operating protocols that create safe havens for wireless microphone users who may encounter interference in the future. The majority of wireless microphone users (who typically use fewer than 20 wireless systems) will be able to operate in designated TV channels that are off-limits to TV Band Devices, thus eliminating the potential for interference. Expanded protection for large events will be provided through a geo-location database. Together these protection schemes will enable both small and large users of wireless microphones to operate without interference from new TV Band Devices.
Reserved Channels Around 37
The 2010 Order stipulates that two TV channels in each market will be reserved for wireless microphone use. These will be the first channel above and the first channel below TV channel 37 that are not occupied by a local TV station. If unoccupied channels are not available both above and below channel 37, the first two channels nearest to channel 37 will be reserved. Because occupied TV channels vary by market, the reserved channels will vary by market also. The channel map in a particular city might look like this:

Because one TV channel can accommodate up to 8 wireless microphones (depending on model), the two reserved channels will allow users to operate up to 16 wireless microphones with no threat from interference from TV Band Devices.
Clear Channels Adjacent To TV Stations (14-20)
Additional TV channels between 14 and 20 will also be off-limits to TV Band Devices due to the technical restrictions that govern their operation. Portable TV Band Devices are not permitted to transmit on TV channels 14-20, and Fixed TV Band Devices are not permitted to transmit on the channels immediately adjacent to the TV channels used by local TV stations or Public Safety agencies. These adjacent channels in the 14-20 range are also effectively reserved for wireless microphone use without risk of interference from TV Band Devices. A sample channel map for a typical city where one TV channel is assigned for Public Safety communications is shown below.

Geo-Location Database Protects Large Events
Large-scale wireless mic users will be able to achieve expanded protection for specific events through the geo-location database prescribed by the FCC in 2008. The 2010 Order requires that every TV Band Device must receive (either directly or through another device) a list from the database of available TV channels at its location before transmitting. Both licensed and unlicensed wireless microphone users will be able to register the date, time, location, and duration of an event and the TV channels used by their wireless systems in the database. Portable TV Band Devices will be prevented from transmitting on those TV channels when they are within a 400-meter “exclusion zone” around that location; Fixed TV Band Devices are subject to a larger 1-kilometer exclusion zone.
Venues must request database registration at least 30 days in advance, and must certify that at least 6 wireless microphones are operating in each of the reserved TV channels available at that location. The FCC will make requests for database registration public and will provide an opportunity for public comment or objections. The Order does not specify who will administer the geo-location database or when it will be operational.
Spectrum Sensing No Longer Required
The 2008 Order stipulated that all TV Band Devices must include “spectrum sensing” technology that would enable them to detect and avoid TV stations as well as wireless microphones that are not registered in the database. The 2010 Order removes the spectrum sensing requirement, concluding that this technology would add cost and complexity to TV Band Devices and would be redundant to the protection provided by the geo-location database. Portable devices that rely on sensing only (without database access) will still be permitted, but will be limited to 50 milliwatts of transmit power and will be required to pass stringent laboratory and field tests to prove that they will not interfere with incumbent users.
No Changes To Wireless Microphone Licensing
Wireless microphone licenses are currently available to broadcasters, television and motion picture production companies, and cable TV networks. In January 2010, the FCC asked for comments regarding to what extent license eligibility should be expanded. The 2010 White Spaces Order does not address this issue, and given the extensive protections for unlicensed wireless microphone users mandated in this Order, it is unclear what importance the Commission will attach to the matter of license eligibility going forward.
What Happens Next
Before TV Band Devices enter the market, the database administrators must be selected; database access and registration procedures must be developed, and new devices must be submitted to the FCC for approval. The Commission is still considering potential changes to the spectrum (including the TV bands) in connection with the National Broadband Plan which raise complex legislative, regulatory, and technical issues that may take years to resolve.

Copyright 2010 Shure Incorporated
Original document found here.

Comment: This is a very valuable document. Shure has clarified an obtuse federal document, and translated into intelligible terms. Practical application: Every wireless mic that was legal before the decision is still legal after the decision, though we may have to be more intentional about our frequency choices in the future.

Opinion: This will definitely affect us, but not for some time. The required federal database won't be available until 2011, and the infrastructure required for such products won't likely be in place until at least 2012.