MISTAKES CHURCH SOUND PEOPLE MAKE WITH MIXING CONSOLES – #8
- Let’s take a deeper look at the signal chain. On the handheld transmitter, there is a sensitivity setting. On the wireless receiver, there is a gain output. This is before we even get to the mixer, and we have 2 gain stages.
This article is part of a series called The Top 10 Mistakes Church Sound People Make With Mixing Consoles. We’re on number 8. Go here for part 1.
#8 Improper gain staging
So much is misunderstood about gain staging in the audio world, especially in church sound.
What is “gain staging?” Gain staging is the process of making sure the audio is set to an optimal level for the next processor in the chain in order to minimize noise and distortion. By gain staging through your analog and digital systems, you can achieve the best possible sound for your recording. [source]
Years ago, Mackie gave these instructions in their mixer manuals about setting ‘gain structure:
Select solo on the channel you are working with and set the fader at ‘unity,’ turn the gain knob up until you have a level on meter averaging ‘0’ or unity.
This is the simplest explanation of setting gain I have ever seen written by a manufacturer. The writers at Mackie were great at injecting humor into often confusing subjects. Let me give you a simple explanation for why setting the gain structure is so important. If you set the gain too low on an input, you will introduce noise into the channel strip. In a digital mixer, you will be digitizing this noise. If you set the gain too high and the pre-amp overloads, you will be distorting the microphone pre-amp, and from that point on in the signal chain you will have a distorted signal.
Most churches I see will have the gain set extremely low because they “don’t want to distort the mic pre on a digital console.” Well, here are a couple of “fail” scenarios your church tech team will want to avoid that I consistently run across regarding gain.
Improper gain staging at the mic-pre
I was hired by an A/V consultant to mix at a church and after I set the gain structure on the console on all inputs during soundcheck I started building my mix. But the consultant wanted to see all my faders at “unity gain” and constantly adjust the gain level knobs so my faders would always be at “0.”
This is not correct gain staging. When I see a sound person with all faders at “0” (unity), it usually is a dead giveaway that they do not understand proper gain structure. Setting the gain level gets the best signal-to-noise ratio for that channel input. The fader position is for the proper volume (different than “gain”) setting in relation to the mix.
Here’s another way of looking at it. If I set the gain structure for cymbals correctly, I may want them lower in the mix than my kick drum. Why? Visually, when I look at the faders, the cymbal will be lower than the kick. That is OK!
Improper gain staging in a mix
I had a complaint about an Aviom system from a vocalist. The singer could not hear herself. So, in her mind, the mixer must not be working properly. Now, I’m not beating up on singers, because I am one, but, common now! The monitor system was working because I checked it before the singers arrived. So I went on stage, put in a set of earbuds, and listened to her mix.
Her IEM pack was at about 9 o’clock, the master out on the Aviom mixer was at about 10 o’clock, and her vocal mic on the mixer was maxed out, as well as nearly all of the other band channels.
I turned the Aviom main output up to 3’ clock, turned her IEM pack up to 3’clock, and turned all inputs on the Aviom mixer off. I then turned her mic up to about 2’ clock (I wanted to make sure she had a little headroom left). I turned up all the other vocal mics until they were just below her mic level. I panned the vocals in relation to where they were standing on stage relative to her. Then I turned up the piano on her mixer to give her a pitch reference.
She thought I had invented the wheel.
All I did was adjust the gain stage of her mixer and IEM pack and rebuilt the mix. The difference was a revelation to her. It was the difference between correct and incorrect use of the gear.
Improper sensitivity setting on wireless microphones
Here’s something that happens a lot; a lead vocalist is distorted in the video mix. The video director gets a message to the front-of-house (FOH) sound person to turn down the lead vocal. The FOH sound person cuts the auxiliary buss on the audio console feeding the video by -3 dB. Distortion is still happening.
When looking at the wireless mic receiver, the audio meter was in constant red. The lead vocal was a different person than last week and they were singing at a lower volume into the mic. Gain on the mic transmitter (called sensitivity on some brands) was boosted +6 dB on the handheld to compensate for the quiet vocal. This week’s singer has a booming voice and didn’t need the extra 6dB of gain. Hence the distortion at the transmitter.
Solution? Turn down the gain (sensitivity) on the transmitter, and it eliminates the distortion. But remember you have to increase the output gain on the wireless receiver by -6 dB to compensate for the reduction at the wireless mic transmitter.
Let’s take a deeper look at the signal chain. On the handheld transmitter, there is a sensitivity setting. On the wireless receiver, there is a gain output. This is before we even get to the mixer, and we have 2 gain stages. Then we have the gain on the mixing console for the mic-preamp. Then you have the input fader level and then the master level. That’s five “gain stages” before we can even discuss groups.
Sending that input to a monitor, you have the auxiliary level of that mic input, then the auxiliary master of that monitor. Then, if you have a floor monitor, you have an amplifier gain stage, or a self-powered monitor, you have a gain stage on the input and output.
These are simple, common audio applications that don’t involve any math. Make sure your gain adjustments are made during line check or sound check. If you have to go back and adjust gain levels during rehearsal, make sure you warn everyone on monitors, especially people using in-ears because it will affect their levels. Be sure to communicate all changes during a rehearsal.
Hopefully, you’ve found this to be helpful advice for your church audio team, but the best advice I can give is to remember to pray with your A/V tech team before the service! You have a built-in, ready-to-serve, prayer team at your disposal and what we’re really doing here is building a community in the way that Christ would want. He cares more about hearts than gain staging.
In the meantime, happy mixing and I hope this article helps you create an environment for worship!
- #10 – Signal Flow At The Front End of the Mixer
- #9 – Not Knowing The Signal Flow In The Mixer
- #7 – Abusing EQ On The Channel Strip
- #6 – Adjust House EQ to Correct Lapel Microphone Feedback
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Michael is a 35+ year industry veteran with a passion for training in the technical arts. He holds a bachelor’s degree in Ministry and Worship Arts. He has a background that includes touring, system design, and consulting, and he has been on church staff as an Audio Engineer, Technical Director, Media pastor, and Worship Pastor. He has been a technical consultant for Air Force Entertainment, written curriculum for Christ for the Nations, and served as Adjunct Professor in the Worship and Tech Arts degree Program. He has been involved in sales and training for numerous manufacturers. He founded LiveWorshipAcademy.com, the first online certification program for church volunteers in the technical arts, and is the Director of Content. He is able to speak into the lives of both artistic and technical individuals, teaching technology as well as the worship theology behind it.