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  • Writer's pictureMatthew Losey

How to Ring Out Microphones and Prevent Audio Feedback | How-to #2

Updated: May 2, 2023


FEEDBACK!

If you’re like me, you are screaming every time some cheesy movie or TV show decides to overdub some feedback when an introverted person walks up to a microphone. That’s not how it works. Feedback just doesn’t happen. It happens for a reason and that reason is someone's fault. Whether someone causes feedback intentionally or unintentionally, feedback’s primary cause is in its title.

Feedback is when a certain sound gets fed into a microphone and then is amplified through the speaker. Since microphones and speakers are not intelligent beings, they do whatever we tell them to do. If improperly set up or improperly used, the speaker returns that sound in the direction of the same microphone and back into the same speaker. You get it, feeding back into an infinite loop until we break that loop.

The best way to stop feedback is to prevent it from ever happening. You probably already knew that. The real question is, “How do you prevent feedback from occurring in the first place?” Planning, preparation, testing, and anticipating potential problems.

Planning

You have to roll back the clock to before any musicians or singers are on stage. Assuming you haven’t designed the PA or equipment, you need to find the best place to put everything. In general, the loud stuff is at the back of the stage (drums, bass, guitars). The quieter things are towards the front (acoustic instruments, worship leaders, etc.) This tends to make the feedback problem worse. It’s not a bad thing though because we can minimize the risks of feedback.

We want the loud things farther away because we want the best experience for the listener and we want the focus to be on the communicators talking or the worship leaders singing. When you’re trying to amplify something quiet, you gain it up. Now there’s feedback.

If you don’t know any better, your first solution is to gain that instrument or microphone down and ride the fader very carefully. That is a solution, but not the best one. Other people go straight to purchasing a feedback suppressor but those are about as good as peeing on a jellyfish sting. It’s better to stay out of the water entirely.

If you want everyone on your team to be as free from stress as possible, aim higher. Aim for feedback freedom.

I am only going to address monitor-caused feedback in this blog post. FOH feedback definitely needs to be addressed, but 90% of all feedback is because of monitors. With that being said, if you have wedges, the easiest solution is to switch to In-Ear-Monitors (IEMs). That’s not the cheapest option though and many times there are special cases that make IEMs impractical. Choirs, Pastors, other communicators, and people who may be hard of hearing. You can either buy dozens of IEM packs or just throw a couple of speaker wedges on the floor and feed them an aux mix.

Preparation

What’s the purpose of monitors? First and foremost, in music, it’s to keep the musician in tune and on time. If we use that qualifying statement, we can get rid of a lot of “noise” in the monitor mix that could become a problem later. If we are talking about a worship leader, they probably don’t need cymbals from the drums or the bass guitar in their mix. That means their own microphone won’t have to be as loud to be heard over the other instruments and inputs in the mix. That will certainly help. Of course, you don’t only have musicians and worship leaders using stage monitors though. Pastors and other communicators also use them to feel generally more comfortable and confident.

Using this information, we can plan for the potential issues from the several possible microphones being shoved into this same monitor mix. Before we ever get to sound check, let alone band practice, the technology and production crews need to have the speakers and appropriate mixes set up. The typical way to feed a monitor mix is with an aux mix from either the FOH board or a Monitor board. Whatever the method, you need to feed the monitor mix through a Graphic Equalizer (GEQ) first, before it is patched to the stage wedge. This way we can do what we call “ringing out” the speakers. It's the single most important step in stage monitors but the most unknown step in most small and medium-sized churches.

You may be wondering why you shouldn’t just use the parametric equalizer (PEQ) that typically is already in line with the aux mix. The first reason is you usually only have one to four options for EQ treatment. That, and it is too debilitating to the monitor mix as a whole. If you are aiming to remove the 500hz frequency, you’ll also sweep out everything around it depending on the width parameters if you even have a width parameter option on your board. A graphic EQ is much more surgical for board outputs. It generally only affects a small specified band around the chosen frequency. You also usually have 10-32 EQ bands to choose from. The rule of thumb here is, PEQ on inputs and GEQ on outputs. Rules are made to be broken so take that with a grain of salt. Not for ringing out monitors though. I’m standing firm on that.

Testing

  1. Turn your whole system on. FOH speakers, monitors, and stage wedges but hold off on all the microphones yet.

  2. Set up your aux mix with the GEQ in line and more importantly, toggled on. I’ve made that mistake more than once.

  3. Assuming all the microphones are appropriately gained and tested already, bring all microphones that will possibly be fed into the stage wedge on stage. Have your audio engineer sit behind the board to handle the GEQ unless you are lucky enough to have tablet-controlled GEQ.

  4. Open up a frequency analyzer on your phone to see exactly what frequency will be feeding back. I like this one and this one.

  5. Grab your most important microphone—in most churches, probably the pastor mic—and with it on and unmuted, start talking into it. Have the monitor engineer turn it up until it’s at a comfortable level and then start looking at your phone for the fun part.

  6. Point that microphone right at the speaker and make it feed back. Force it to feed back even though it’s a miserable sound. Look at your phone while you’re doing it and notice the huge frequency spikes. You are probably going to see two or three. Choose the largest and call that out to your monitor engineer. Let’s say 800Hz.

  7. Have them turn down the closest frequency to 800Hz that they have on the GEQ. Tell them to stop when 800Hz goes away on your analyzer. The microphone will still probably be audibly feeding back but now in a different frequency range. Let’s say 1600Hz is the loudest now. Repeat this process for each frequency until it goes away audibly and visually on your analyzer.

  8. Now test the microphone again by talking into it and have the engineer turn it up or down until it’s at a reasonable level in the stage monitor.

  9. Wave that microphone about a foot away from the speaker and you shouldn’t hear a thing. Now do that for every microphone you brought with you. You probably also want to do this with acoustic guitars because their pickups and internal microphones are notoriously feedback prone.

Anticipate

It sounds like a long process but each microphone should take less than a minute and you’ll get faster at it. Unless you are setting up from scratch each week, you don’t have to do it each service. Resetting your GEQ monthly and ringing it out again would be enough to keep it fresh with new environments, instruments, etc.

After the process is over you should expect the stage monitor to sound a little less lifelike. That’s okay though because you aren’t using it as a reference speaker. The purpose of a monitor is to keep musicians in tune and on time while increasing the confidence of a pastor or other communicator. It doesn’t matter what it sounds like as much.

If you can anticipate feedback problems, you can prepare and prevent them from happening. I don’t like when everyone looks to the back of the room when feedback happens so I’m pretty motivated to do a good job. You can ring out any microphone. As long as it is going to be fed into the monitor, it needs to be. Pastor’s headsets, wired mics, wireless mics, and especially “pulpit” mics will all benefit from being rung out.

All that’s left is to teach proper mic position and placement to your musicians. Every microphone should be pointed away from a monitor and handheld microphones need to be held close to the face, not at the waist. Use this information wisely!


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