How To Set The Gain On Your Mixer Or; Gain Structure Simplified

I have read many different thread posts giving advice on how to set the gain on a mixing console. The options presented have been interesting, to say the least, sometimes humorous and a significant amount of time just wrong. So, this is an attempt to present the concept and application of gain structure in layman’s terms to the degree that it can be done.

First, what exactly is the gain structure of a sound system? It is setting the input levels of each device in the system; mixer, processor(s) and amp(s) in such a way that the sound in the room is loud enough for the application without pushing the levels of any device in the chain into distortion or over their capability. In most applications the processor(s) and amp(s) levels will be set by the system installer and will not need attention from the sound engineer. A quick side bar on this is that if the amp(s) or speaker(s) are undersized pushing the mixer or the processor will not be able to overcome the deficiencies. I have seen sound engineers drive their mixer levels in the red or in other words, distortion, in an effort to bring the room sound up to desired levels.  Obviously, this is not the right solution.

Let’s address how to set up a mixer correctly: First, we must establish that from an operational standpoint we want the faders to be able control the levels of the device on each channel from no level to the max we would ever use. That is not to say that the fader is to remain at 0db during the entire time the channel is in use. I have heard that concept given as a rule of good engineering, it is not.

Second, we must understand the function of the Gain control on a mixer channel. To fully understand this we must understand that it’s function is to match the levels of disparate input sources to each other. It is not another volume control per se. An iPad and a microphone do not have the same output levels (voltages) therefore if they are both connected and the gain is set the same on both channels the fader on the one will be higher than the other to reach an equitable level in the room.

In addition to the various device output levels, there are infinitely different levels of the program materials, i.e. not all music tracks are recorded at the same level and not all singers sing at the same level and not all persons speaking talk at the same level. And not all mics output the same level even from the same models taken out of the box at the same time. So the purpose of the Gain control on the mixer is to bring all of those variables into alignment so that the sound engineer can have proper control of the mix throughout the entire event. The question is how to do that and here are some steps that I use. Some are easier than others to administer so individual adaptations will be in order.

It is assumed for this exercise that we are addressing setting levels on microphones and not other devices that may be connected such as guitars, drums or other musical instruments. While the basic concepts remain, setting procedures will be different.

For this instruction we are addressing only one channel with a microphone connected. To revisit a goal from above, we want to end up with the fader on 0db without feedback after we have completed this routine. First, set the gain control all the way counterclockwise. Make sure that all controls in the EQ section are set to twelve o’clock. And make sure all of the monitor (Aux) levels are all the way down. Once those steps are complete, push the fader all the way to the top of its path. Slowly turn the Gain control up or clockwise until you hear the first signs of feedback and then back it down ever so slightly. Now pull the fader down to the 0 db mark on the indicator scale. For most applications this will be adequate to provide the max needed level control with the fader and you can be confident that the possibility of feedback is minimized. Also be advised that with each mic that is open there is a system gain of 3db toward feedback. If you are using multiple mics, especially in close proximity to each other you may need to perform the above routine with more than one mic open at the same time setting them each simultaneously as indicated above.

As with everything in this world there is always a variable. It may be that after you have set the mic(s) as suggested above you have a singer who is singing at 110db and uses the mic close to the mouth (that is the correct way to use a mic, by the way) and with that, the input level is way above the other singers in the group. How do you set that gain? At this point, hopefully during a rehearsal, we need to adjust the gain so that at the softest point in the music the fader is at or near 0db. This will give the ability to pull the fader down when the singer is exceeding acceptable levels for the mix but have enough headroom at hand for softer passages if needed. Again, there is nothing untoward in having a fader operating anywhere on the scale as needed. There is no need to continually reset the gain. One properly set there is no need to readdress that setting.

How about that peak or clip light next to the Gain control? If your mixer has a clip light or an LED strip indicating input levels, it is used to assist with knowing when the input levels are causing clipping in the signal chain. If the indicator shows the channel is clipping then the Gain must be reduced until the clipping stops. For typical mic usage there is no need to ask the user to pull away from the mic or sing/talk softer. Make the adjustment at the gain control. If the input that is clipping is connected to an instrument or amplifier output it is possible that too much voltage is being sent from the device to the mixer. In that case you will have clipping no matter where the Gain control is set. The resolution for this situation is to reduce the levels from the device to the mixer. There are too many variables in this scenario to address in this format.

So what about the very soft singer? Using the first method above is really all you can do because any additional gain will introduce feedback. Obviously getting the singer closer to the mic will make the program material more available to the mic to be picked up but if that can’t be accomplished there is nothing else that can be done. Maybe I’ll address mic usage in a future post. Feedback control might be another topic to address that fits in with this one.

Does Your Facility Need A Hearing Assist System?

There is a significant portion of the general public who have a hearing impairment at some level. The percentage of persons with hearing loss at some level increases significantly with age. As we consider the impact on the listeners in a public meeting venue we must address a solution from several angles.

First, we must consider what is actually happening that makes a person not understand what is being spoken. The major consideration is the ability of the hearer to decipher consonants which makes a significant portion of the words we speak take on meaning. For example, the words bad or back or bat are extremely similar except for the very last sound, which makes up the real meaning of the word. The last sound is a hard sound and lasts for only a millisecond. Another term for these hard sounds is sibilant. Sibilant sounds are very high in the audible frequency spectrum and, significantly, the very range where hearing impairment is impacted the most.

When addressing this issue in terms of a larger meeting space, such as a church or meeting room, this becomes a real issue since the sibilant frequencies are the hardest to propagate throughout a space. There are three areas of consideration when designing a room for sound reinforcement. They are as follows:

  1. Sound reinforcement system.
  2. Room acoustics, reverberation etc.
  3. Hearing assistance for impaired listeners.

Let’s look briefly at each of these areas:

Sound reinforcement. For the sibilant frequencies in the room to be pushed to each listener in the room consideration must be made to provide a loudspeaker and speaker array design capable of delivering the frequencies to each seat. The sound must arrive only once at that location at a level that is audible with secondary sound arriving at a significantly lower volume level. Proper design of this portion of a space requires computer modeling and a professional system designer.

Room acoustics. Each space has its own acoustic characteristics and the larger the room and depending on design the more reflections, reverberation or echoes develop with sound movement in the space. AS the secondary sound arrives at the listener’s ear somewhat in time after the original sound it will conflict with the original sound making it difficult or even impossible to decipher what the original sound was. And again, this clarity problem is the most problematic in the frequency range of sibilant sounds. A study of the room’s reverberant qualities must be undertaken using computer modeling and strategically placed acoustic modification must be undertaken. This generally takes the form of acoustic damping panels but can also include several other solutions. Auralex is a product specifically designed to allow an engineer to apply a fix to a space.

Hearing Assistance systems. for some people the solutions above are not sufficient to allow them to participate in the service. For them a special assistance system which can amplify the sound through an earphone or hearing aid system is the only solution. These systems can use an independent radio receiver that the listener uses with an earphone to receive the sound from the microphone directly in the ear. An alternative system called a T-Coil can be used to transmit the sound through radio waves from a personal receiver directly into a T-coil hearing aid. There are also more elaborate and expensive systems that incorporate an antenna loop around a room under the floor that directly sends radio waves to the T-coil hearing aids. Williams Sound is a company who provides such systems.

A word about the Americans with Disability Act or ADA regulations. ADA web site, click here. The ADA does require that certain rooms used for public gatherings must provide an assistive listening system. Churches are exempt from the ADA requirements but many churches do provide a system for members and attendees as a courtesy and as a way to assure all persons can understand what is being said.

This article only touches the surface of the information relating to this topic so here are some additional resources for those who may need more in-depth information.

Williams Sound: ADA white paper.

Healthy Hearing:  Rights for those with hearing loss.

Hearing Health Matters: That pesky ‘S’.

Sound Concepts is qualified and has the computer software and training to study your space and provide a solution and costs to improve the acoustic characteristic of your sound system and room acoustics. Please feel free to contact us for a free initial consultation.

Visit our section on acoustic treatment.

Why Acoustical Treatment In Performance Spaces

Most large performance venues such as Houses of Worship, theaters and large conference rooms have issues with reverberation, echoes and things like early reflections. These mystical things interfere with the listener’s ability to understand the content in the presentation be it spoken word or music. Our ability to decipher consonants, s, t, b and the like, which are short bursts of higher frequency sounds, is significantly decreased when the sound arriving at the listener’s ear is interfered with by other sounds left over from previous sound waves (words).

So how do we solve this problem? Some rooms are designed to minimize these unwanted sounds by installing non-parallel walls or walls that have cavities in them called Helmholtz resonators and a variety of other architectural design features. However, most buildings are designed in a square or rectangle design pattern with square corners and hard surface walls all of which add to the problems we are facing. The overarching objective is to have the original sound from the person speaking or the music arrive at the listener’s ear without be interfered with unnecessarily. (Some reverberation is important and necessary but not for discussion here.) Since the interference we are talking about comes from the original sounds hitting the surfaces of the room and then coming back into the room, those sounds arrive at the listener’s ear during the time the next original sound is arriving at the listener’s ear. So, at any point in time the original new sound and the reflected or left-over sound from the previous sound are arriving at the same time. So, the brain must sort out what it already heard from what it is hearing for the first time to be able to understand what the new sound is. Depending on the strength of either of the sounds and how much later in time the reflected sounds arrive at the listener, it may be impossible to actually tell what is being said. The severity of this issue will corelate to the position of the listener in the room and other factors like ambient noise say, from the air handler.

The resolution, in simplified form, is to minimize the reflected sounds and amplify or properly direct the new original sounds. For a room where architectural changes are impractical, generally the first item of business is making sure that a properly designed reinforcement speaker system is installed in the room. For more on this see the section on sound system design. The second issue to address is surface treatments. These most often take the form of sound deadening panels. Other treatments include sound deflecting panels or devices, wall banners, ceiling banners and a host of other treatments.

So how do I now which treatment is right for my room? The auditory frequency spectrum is quite large, 20 to 20,000 cycles (Hz) all inclusive. The material that will reduce the unwanted 20Hz may not impact 20,000hz at all and in fact may make the situation worse. To determine the impact of a treatment option on a space, a lot of complicated mathematical calculations are required. Originally these were done by hand by individuals trained in that science. Today however we have several software apps that perform the calculations for us after we enter the required room dimensions and other considerations. Not all of these apps are created equal however. Some apps simply determine what material combinations can be used to reduce the sound levels in the room without regard to the individual frequencies or for propagation of original sound. These apps are good for making industrial spaces tolerable but not particularly helpful for a performance area. We use a software called EASE which is designed specifically for performance spaces and can take into consideration every nuance of the space and the sound system as well. From studies performed by this software we can determine the optimal materials to reduce the unwanted sounds in the room while minimizing the effect to the good or desired sounds in the room.

Before purchasing and installing any materials in a space an EASE study must be done to be sure that the money being spent on materials and labor will actually perform the desired task. Too much damping in a room can be just as detrimental as not enough. Contact us for no cost initial site visit and to determine what the cost is for a complete room analysis. It is much better to get it right the first time rather than have to go back and redo the project later.

How Bright Does The Projector Need To Be?

To determine the correct projector to specify we need to take a look at the purpose of the projected image. Is it for a classroom, home, church or other public venue? Another consideration is what is the intended content to be displayed? Words on a solid background? Video with moving images? Pictures? Spreadsheets?

So what are ANSI lumens, besides being the accepted measurement of the brightness of a projection device? From Wikipedia: “The lumen is the SI derived unit of luminous flux, a measure of total quantity of the visible light emitted by a source.” And more: “ANSI lumens: The light output of projectors (including video projectors) is typically measured in lumens. A standardized procedure for testing projectors has been established by the American National Standards Institute, which involves averaging together several measurements taken at different positions.” So what does that mean in a real world environment?

First let’s look at the intended use. If the image to be displayed is a simple plain background with words in a contrasting color, say black letters on a light blue background, a lower lumens projector may well do the job. The contrast in the image is high and so the eye does not have to decipher small color variances to understand the image. It should be noted that the viewable font size plays a role here as well. A spreadsheet with a lot of numbers and lines will require more light levels and greater contrast from the projection device to be able to present an image so the viewer can clearly determine what the characters are. However, if the intent is a picture or video the light levels must be considerably greater to be able to show the true colors at a real world intensity level. Contrast also plays a significant role in this issue but that discussion is for another time. Suffice it to say that more contrast is better.

Second, what is the venue? If the image is being displayed in a home theater with no ambient light a fairly low ANSI lumen level projector will provide a very acceptable viewer experience but if the venue is a Church with natural light coming from windows or if the service is operated with the house lights turned up, a significantly greater light from the projector will be required.

For the home theater a 2000 ANSI lumens projector with good contrast ratings and high resolution may provide a great viewer experience. However, a 10,000 ANSI lumens device may be required in a Church or other public venue depending on a variety of room related factors. Obviously budget comes into play about now in the discussion and often a compromise has to be reached. To determine where to land on this discussion some time must be devoted to a site investigation with a professional to determine how best to provide a suitable image at a manageable cost. Can the screen be positioned in shadows with little or no light shining directly on the screen location. Can the room lights, or a portion of them, be dimmed or redirected to provide a more viewable atmosphere. These are among the questions an experienced performance room designer can ask and answer.

There is no hard and fast rule regarding ANSI lumens other than it is nearly impossible have too much light while it certainly is possible to have too little light. With the cost of projectors dropping continuously, more brightness can be had for a very reasonable cost. The first projectors we installed in Church venues were 2500 ANSI lumens and cost $10,000.00. Today we are recommending 6500 – 7000 ANSI lumens projectors for most smaller churches at a cost of around $3000.00. It is always best to call a designer and have a professional look at the facility and make suggestions before spending money only to find that the determined solution is unsuitable or even unusable.

Is Livestreaming Your Event A Good Idea?

Many churches I visit these days are doing some sort of streaming of their services. While this is common today it was not at all common when I first streamed a live service at Hope Church in Mason somewhere around 20 years ago. There was no possibility of video and the audio only stream was glitchy and poor quality. But, we wanted to make the message available to more people and we foresaw the trend that how content was consumed was about to change significantly.

Fast forward to today and I have been assisting Anderson Hills UMC in setting up streaming for both their Traditional and Contemporary worship services. Along with an associate we have configured the systems to stream a full 1080P video image with almost no glitches providing the viewer a great, high quality experience.

So how about the value to the church? When we started streaming way back then it was difficult to know how many viewers we actually had. After we upgraded at Hope Church about 15 years ago and included video and converted from Real Media to Windows Media, we were able to have an online monitor of the streams and, in real time, view the ip address of those logged in and where they were coming from. I was very surprised to see that we were getting viewers from all around the US and, if I remember correctly, we had around 100 simultaneous viewers pretty much on a weekly basis. And this was without the benefit of any marketing or social media, just word of mouth and the church website. Today churches like Crossroads have tens of thousands of online viewers each week.

So I would ask, why would a church not have a livestream setup for their services? It allows a way for shut-ins to see the service live, those on vacation or away on business to feel connected. And family members who have moved away to stay in contact. And with the on-demand feature, archived services can be viewed at any time, anywhere in the world. For me this is an essential feature for every church that is serious about personal ministry and instruction to anyone and everyone.

Sound Concepts is partnering with a local hosting company to make streaming affordable even for the smallest of churches. We are offering a service whereby the church no longer requires an internet savvy person to be available at the beginning and end of each event. We will arrange for the stream to begin and end automatically each week. Nothing to do but start the service and thereby reach people that otherwise would not be reached. If this is of interest to you please give me a call and I will be glad to discuss the requirements and program details. Or you can click this link to read more about what we are offering.

Sound Concepts Livestream Webpage

So What’s This About Banned Wireless Mic Frequencies?

FCC Banned Frequencies Update
The FCC has recently auctioned off a band of frequencies that have previously  been made available for use with wireless devices including wireless microphone systems. To see the actual statement by the FCC visit this website:
The practical effect for any current user of wireless microphone systems is that, depending on the frequency range of the systems in your church, school or other facility, it may become illegal to operate your systems in the near future.
First, the affected frequency range: 607-698 MHz Note: all systems operating in the 700 MHz frequency range were banned several years ago and are illegal to operate now.
Second, How to check your systems: Each transmitter and receiver will have the frequency range listed on the identification tag or in the settings menu. The format is generally shown as MHz. or MHz.
Third, when will it become illegal to operate systems: All operation of the affected devices must cease by the end of the day July 13, 2020. However, there may be some new legal devices operating now in range they have been allocated.
Fourth, what options are available to address this issue?
1. One option is to keep the offending system(s) until the deadline date and then begin using a system operating within the legal bands.
2. Another option is to purchase a new system(s) now.
3. Another option is to choose an option other than the wireless system.
Considerations: The offending system still have some resale value on eBay and other marketplaces. Selling now will result in some return on investment. As the date to cease operation approaches the value will decrease to 0. During the last round of replacements, the 700 MHz band, we were able to donate a significant number of wireless systems to missionaries in countries other than the United States as it is only illegal within the borders of the U.S.
For more information on this issue you can visit the Sennheiser website discussion on the issue at:
The Worship Facilities website also has the following article on this issue:

Why Do Churches Often Buy Several Sound Systems In A Short Period Of Time?

I can’t tell you how many time I have visited a church to look at a sound or presentation system that they are unhappy with only to hear the pastor say “We’ve  only had this system a few years but it has never been right” After a few probing questions the answer is almost always the same; “We used a guy who was a friend of a member of the church.” Or “It was installed by our sound guy.” I’m sure there is the thought that the person was a really good fellow and would give them a great price but it did not work out as planned. So why is that?

In my experience, most “sound” guys are only sound mix engineers and not system designers. Maybe they run sound for the local band or even are the sound man at a local church, but, does that qualify them to design a system for a permanent installation? Let’s look at a couple of scenarios:

Sound guy for a band: This person may, in fact be really good at making his band sound great in the local restaurant but there are significant differences between that venue and a house of worship.

1. A restaurant venue is generally smaller than a church Sanctuary and most certainly has a lower flat ceiling.

Response: Most Sanctuaries are significantly larger than a restaurant dining area. In addition most Sanctuaries have vaulted or domed ceilings or if they are flat they are generally 2 or more stories high. Sound propagates very differently in a larger room than in a small space. Speaker placement becomes critical to even distribution and clarity of sound to each seat. A very different loudspeaker is required and must be matched to the dimensional characteristics of the space where it is to be used.  Most certainly all speakers are not created equal.

2. The audience for a band concert is likely to be talking to others they are dining with and the music becomes only ambiance or background entertainment.

Response: When we are dining out our attention is primarily on the persons we are with and the conversation going on around us. When in a church service or other spoken word event the attention is focused on the person speaking. In the restaurant there is no real need to understand or really comprehend the content of what is going through the sound system in contrast to the need to comprehend every word coming through the sound system in a house of worship.   It therefore becomes critical that the sound arriving at the listener’s ear be clear, orientated such that it appears that the sound is coming from the person speaking and not from somewhere in the room and that the sound arrives only once to the listener at an audible level. Room acoustics, speaker design and placement enter significantly into the design equation if we intend to have clean, clear sound.

3. Most likely the same people will not be back within a week to hear the same band in the same location.

Response: Attendees of a house of worship generally attend week after week and, more often than not sit is a similar place in the room. If the reinforcement system is hard to listen to for the reasons listed above they will start to complain and after a while may even stop attending the services.  Proper design and implementation is very important in maintaining the attention of the attendees.

3. Very little of a band the event is spoken word.

Response: In a typical worship service or lecture, at least 50% of the event is spoken word. In our restaurant example, such a small amount of the event is speaking that the listener may be willing to strain to understand for a few sentences but if the speaking goes on for a time and it is difficult to understand the words the listener will fatigue from the required effort and either tune out or leave altogether. Again, proper attention to the acoustics of the space and the design of the speaker system is critical to the success of a sound reinforcement system.

Sound guy for the church or some other church: This person may have experience setting up sound week after week when the church was a startup and was asked to do the install for the new building. So he really should be able to design a permanent system, right? Or maybe the sound guy has been in the church for many years and has faithfully shown up week after week without pay, contributing to the ministry of the church with his time. Of course we have to let him do the design and installation of the new sound system, it would not be right otherwise.

I’m not going to repeat all of the items above because they mostly apply here as well. While the sound guy is dedicated and a friend of everybody in the church does not mean he has any knowledge of acoustics of a given type of space and such things as RT60 or %ALCONS or a significant number of other criteria that must be considered in planning speaker choice and location. And even if he understand the meaning has he ever really had to deal with these issues in different venues each with their own anomalies.

So what is a church or pastor or leader to do? First, be sure that you consult with a company that does have experience in designing larger spaces and most specifically performance spaces. If possible visit several facilities with similar characteristics and needs as are found in the project you are developing.

Except for the smallest of performance spaces, an EASE study (click here for more information) must be completed. In this study the coverage patterns of the speakers will be made clear and the acoustic characteristics of the space can be quantified. Do not buy a system without it!

Just because someone can hook up a stereo system and make it work or can set up a system for the Friday night band gig does not mean they have the knowledge to implement a successful performance system in a large room or performance facility.

Jim Murphy, Owner, Sound Concepts LLC © May not be reprinted without permission.

For another perspective on this issue here is a resource with a slightly different take on the issue: Why Churches Buy Three Sound Systems, and How You Can Buy Only One