Feedback is a MAJOR worship distraction! And it’s something that some churches deal with on a weekly basis. Even churches with paid professional sound techs can have feedback if they don’t follow a few simple rules!
What causes feedback? And how do we keep it from disrupting our worship?
We recently covered a few quick ways to stop feedback once it starts (check out that post here).
But what can we do to stop it BEFORE it even starts?
Just to recap…
Feedback is the result of sound looping between an audio input and an audio output.
This normally happens whenever a microphone is placed in front of a speaker that is supposed to amplify whatever is coming from that microphone.
Need a visual of how that works? Hold a mirror in facing into another mirror. That’s visual feedback. The audible variety is just more painful!
Stop Feedback at the Source
There are two important rules to follow if you want to prevent feedback.
- Don’t place a microphone in front of a loudspeaker.
- Place the microphone as close to the source as possible.
There are some common instances where rule #1 is violated. Pastor walks out in front of the main loudspeakers. An acoustic guitar player bends down in front of the stage monitor. A microphone is passed around the congregation for announcements or testimony. Etc…
If at all possible, keep active microphones behind and pointed away from loudspeakers.
If that isn’t always possible, or you’re still having trouble with feedback, explore rule #2.
Keep microphones close to the source.
This is normally pretty easy for vocals. Miking instruments and choirs can sometimes make this a challenge though.
Let’s go into a little more detail with this one.
Microphone tips for preventing feedback
Your first job is to select the right microphone.
Pay attention to the “pattern” of the microphone. Microphones are available in different directional pickup patterns. Omni-directional microphones pick up sound 360° around the microphone. Cardioid pattern microphones pick up sound mostly in front of and around the sides of the microphone. And super-cardioid microphones have an even narrower pickup pattern. (See illustration below.)
Cardioid microphones are probably the most popular and effective choice for your average live sound applications.
One of the biggest challenges in church sound can be controlling feedback from the pastor’s mic.
Clip-on lavalier microphones are a common mic to use for pastors and other presenters. The problem is that it can be challenging to place the mic close enough to prevent feedback.
For best results, you should try to place a cardioid pattern lav mic 6-8” below the chin. Too close and you may get too much of a deep or throaty sound. Too far away and the sound will be thin – and you’ll have a higher chance of feedback.
If that still doesn’t work, you may need to use one of the increasingly popular low-profile earworn or headset microphones available. These microphones clip over the ear or around the head and allow the microphone to be really close to the edge of the mouth. Point Source Audio and Countryman make some pretty great mics for this.
Since we’re talking about vocal mics, here’s a quick tip: engage the low-cut or high-pass filter on your console for vocal mic channels. This cuts off frequencies below 100Hz that can cause unnecessary rumble and low-end feedback.
For choir and instrument miking, you may find super-cardioid microphones useful to capture a really tight pattern of sound at a distance. This can keep monitor noise and stage volume from entering the mic from the sides.
And speaking of stage volume…
A discussion about feedback would be incomplete if we didn’t talk about volume. Namely, stage volume.
I can’t tell you the number of times I’ve encountered a feedback problem where the best solution was to simply turn it down – just a little bit!
The audio source present at the microphone must be louder than the background noise from the speakers. If we can decrease the volume in the speakers just a tiny bit, perhaps that vocalist can be louder in the microphone than their stage monitor.
Keep a handle on your stage monitor volume. Some churches use personal monitor systems to help with this. Just remember that you always have the option of turning it down!
Go forth and … practice!
So, those are some quick tips and rules to follow for stopping feedback before it starts.
There are ways to bend those rules, IF you use certain microphones, loudspeakers, EQ, and other mixing techniques. But you’ll always be safe if you abide by the fundamentals mentioned here.
Experiment with microphone placement, using different microphones, and controlling your stage volume. Move on to more advanced techniques like EQ if you still can’t get the sound your after.
And if you still can’t get it under control, don’t be afraid to call in a professional. There are many qualified pro audio contractors and technicians that can help with your sound system needs. A one-hour visit might be all you need to get you on the right path!
Have questions about how you can stop worship distractions and improve your church sound? Feel free to let me know!