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We all dread noise, especially the high pitch noise coming from a microphone.
To fix those high-pitch noises, you need to understand what causes them in the first place.
Technically, that dreadful screeching noise is called feedback.
Feedback occurs when a microphone picks up the loud sound from the speakers and re-amplifies it.
This creates a continuous loop which results in an unpleasant screeching sound.
It is not only annoying but can also damage your ears as well as your sound system.
Table of Contents
How to Fix High Pitch Noises Coming From a Microphone
Feedback is bound to occur when you use microphones and loudspeakers in the same space.
We have already seen the factors that influence microphone feedback.
So how to eliminate the high pitch noise coming from a microphone, for good?
1. Place your microphone properly
Microphone placement is an essential part of eliminating microphone feedback.
It is critical to understand how and where to place your microphone in relation to the speakers.
So how do you go about this?
The Microphone Position in Relation to Loudspeakers
Firstly, place the microphone in a way that the loudspeakers aren’t feeding directly into the microphone.
Preferably, place your microphone behind the loudspeakers and point them away from the speakers.
Never point at the speakers with a microphone because most microphones will pick up sound from the front and reject sound from the back.
So always keep the front of the microphone pointed at the sound source.
The Distance Between the Microphones and Loudspeakers
Move the microphone far away from the loudspeakers but, still, keep it close to the source sound.
The further the microphone is from the loudspeakers the lower the chances of getting feedback.
The Microphone Position in Relation to the Sound Source
Move the microphone closer to the sound source.
If you are speaking into a microphone, don’t hold it away from your mouth.
The closer the microphone is to the sound source, the clearer is the audio output.
The microphone won’t pick up as much of the surrounding noise, which will also eliminate feedback.
2. Hold Your Microphone Properly
The person speaking into a handheld microphone will determine whether feedback will occur or not.
In most cases, the presenters/performers at a live event bring about microphone feedback because they lack the training on proper microphone holding techniques.
So, what are these proper techniques for holding a microphone?
To capture the voice as clear as possible while rejecting other sound sources and as a result to eliminate feedback, a presenter/performer should understand these techniques:
- Understanding the type of microphones and how they work
- Holding the microphone securely and close to the sound source
- Pointing the microphone away from the monitors
- Using directional microphones
- Avoid cupping the microphones
- Movements on stage
- Adjustments during soundcheck
Hold the Microphone Securely and Close to the Sound Source
Holding the microphone close to your mouth or a sound source will allow it to pick up more of the intended sound and less of the unwanted sound in the environment.
Additionally, holding the microphone securely with all your fingers will limit it from moving a lot, otherwise, the extra handling noise can be amplified and cause feedback.
By capturing a more direct, clear, and clean sound, the microphone will gain less noise from the surrounding which means less output from the loudspeakers which in turn, reduces the chances of feedback occurring.
Point the Microphone Away From Monitors
Monitors are placed on stage and pointed towards the performers to help them hear themselves during a live event.
Most microphone polar patterns are designed to pick up sound from the front and reject sound from the back in live sounds.
Teach your presenters beforehand to be careful to avoid pointing the stage monitors with the microphones or specifically to point the monitors with the tail end of the microphones, unless you want the wrath of feedback to rain down on your audience.
Using Directional Microphones
As mentioned earlier, directional microphones are the most convenient for use on a live stage because they only pick up sound from what they are pointed at.
On the contrary, omnidirectional microphones are prone to feedback since they capture sound from all angles and directions.
So, directional microphones are the best for anyone speaking into a mic because they increase the amount of gain before feedback.
Avoid Cupping the Microphone
Performers such as rappers think it’s cool to wrap their hands around the microphone capsule which covers the grille, which makes a terrible sound that can result in feedback.
Covering the holes of the grille with your hand turns your directional microphone into an omnidirectional microphone that reacts to sound from all directions.
When trying to eliminate microphone feedback, presenters and performers should be advised to avoid as much as possible cupping the microphone because this is a poor technique of handling microphones on stage.
Movements on Stage
A handheld microphone comes with the freedom to move around on stage.
So, how will movements on stage influence your microphone sound?
To reduce microphone feedback as you move around:
- Always remember to keep the microphone pointed at and closer to your lips
- Avoid going near loudspeakers and monitors or being in a position where the speakers and monitors point at the top of your microphone
- You don’t have to move around; you can put your microphone on a stand to minimize movements on stage all together
3. Check the Placement of the Loudspeakers
Another way of eliminating the high pitch noise is by positioning your loudspeakers the right way.
Place Your Loudspeakers Forward
Keep your loudspeakers away from the microphone and closer to the audience.
Placing loudspeakers forward increases the distance from microphones and eliminates the possibility that the sound from the loudspeakers will bounce back to the microphone.
Besides, with speakers closer to the audience, the audience will hear a clearer sound straight from the source.
Point Your Loudspeakers Away From the Microphones
It is not enough to keep the loudspeakers away from the microphone.
You have to position the loudspeakers correctly.
They must not face the microphone (sound source) but have to be placed in the opposite direction.
This will also prevent the sound coming from the loudspeakers from bouncing back to the microphone.
Point Your Loudspeakers Away From Reflective Surfaces
Avoid aiming loudspeakers directly at reflective surfaces and walls to cut the amount of sound that bounces back to the microphone.
Instead, point your speakers towards the audience so that the sound is clear and clean.
Also, you can use carpets and soft fabric such as curtains in space to prevent sound from reflecting on surfaces.
4. Check the Type of the Microphone
Understanding the different types of microphones and their structure is important.
To reduce high pitch noise and suppress feedback, use cardioid and super-cardioid types of microphones.
These are more directional and result in better isolation and high resistance to feedback as they have the ability to reject unwanted sounds.
Using omnidirectional microphones has a downside because they lack the ability to cancel out background noises and are prone to monitor feedback loops.
5. Check the Microphone’s Input
Let’s see how microphone input does not increase the risk of feedback.
Don’t Turn up the Volume
Most people tend to increase the volume of a microphone instead of bringing the microphone closer to their mouth.
This increases the sound coming out of the loudspeakers, which the microphone picks up again.
So do not turn up the volume any more than it’s needed; instead, hold the microphone close to the mouth.
Turn Down the Volume
One of the most effective and quick fixes to feedback is to find the microphone that is causing it and turn down the volume from the audio mixer immediately.
Simply put, turn down the volume of the offending microphone.
6. Check the Loudspeakers’ Output
Lower the volume of the loudspeakers to the level that is needed to prevent the microphone from picking up sound and thereby creating a feedback loop.
Again, make sure to place speakers closer to the audience than to the sound source.
7. Check the Number of Open Microphones
Having more open microphones can increase the occurrence of feedback.
To fix this, limit the number of microphones in use and turn off those you are not using at that moment.
By reducing the number of microphones in use, you will achieve clarity and better audio output quality.
Besides, you will have the chance to quickly correct feedback if it still occurs.
Reduce Microphone Sound Competition
For instance, in a live band, other musical instruments might be playing too loud that the sound from the microphone is inaudible.
This technique might not necessarily reduce feedback but it will help prevent turning up the volume of the microphones.
Consider putting the microphones farther from other musical instruments so they pick up less sound from them.
8. Equalize the Sound
Sound operators use the term “ringing out” as a method of detecting resonant frequencies that cause feedback and reducing it by equalizing the sound systems.
Feedback occurs at different frequencies depending on the volume of the microphone.
Carry out a few soundchecks to detect and ring out the offending frequency by filtering resonant frequencies out of the sound system mix.
To eliminate microphone feedback by sound system equalization, you can use either of the following 3 types of equalizers:
- Graphic EQ
- Parametric EQ
- Automatic feedback reducers
A graphic equalizer is an easy and quick way to remove frequencies that cause feedback.
This process simply involves slowly turning up the volume of the microphones on a stage until you begin hearing feedback.
Ring out the room by detecting the offending frequency and cut it.
Parametric equalizers are more complex and capable of making precise sound adjustments than graphic equalizers.
This method involves sweeping a boost across a range of frequencies to find the offending frequency and then cut it to cancel out the feedback.
Automatic Feedback Reducers
Automatic feedback reducers are tools that reduce the risk of feedback occurring by automatically adjusting the equalizers.
These tools use a microprocessor that detects and automatically reduces the offending frequencies before feedback even occurs.
Automatic feedback reducers work effectively if your microphones are handheld, wireless, or if you have many open microphones on stage.
They are convenient if your ears are not trained to detect an offending frequency quickly or if you don’t want to keep on checking for offending frequencies.
9. Check the Type of Monitors
Replace loudspeaker monitors with in-ear monitors or headsets you can use to listen to your performance while you are playing music, speak, or sing.
By removing loudspeaker monitors from the stage, far from the microphones, you significantly lower the chances of feedback occurring.
The in-ear monitor is expensive compared to the speaker monitor, but if you can afford it, go for it because it’s worth it.
10. Beware of Room Acoustics
Room acoustics describes how sound behaves in an enclosed space.
Each space and every object in it react differently to different sound waves.
You do not have control over this factor as it depends on the space or room the microphones are being used.
Even after following all other factors to eliminate feedback, sound from the loudspeakers might still hit a reflective surface and bounce back to the microphones creating feedback.
So, how do you know if your space has good acoustics?
These factors play a crucial role in shaping the acoustic profile of a given space:
- The size of the room
- The shape of the room
- The materials used in the construction of the room
- The height of the ceiling
- Reflective or absorptive paneling
- The choice and positioning of furniture
How to Treat Room Acoustics
The acoustics of a given space can either make or break an experience.
In a room, sound waves are either absorbed or reflected by the surfaces, structures, and materials in that room.
To minimize the occurrence of feedback in a given room, you need to increase the surfaces that absorb sound waves and reduce the reflective surfaces.
Soft porous surfaces such as carpets, fabric curtains, furniture, and panels absorb sound waves while flat, smooth surfaces such as walls, tables made of glass, and large windows reflect sound waves.
Some of the fast and easy fixes to improving the acoustics in your room is to add things like carpets, fabric curtains, upholstered furniture, specialized acoustic panels to reduce sound reflection.
You can also incorporate automatic feedback reducers into your system to quickly detect offending frequencies and control possible feedback before it gets out of control.
Adjustments During Soundcheck
During soundcheck, the sound system is adjusted to make sure it is producing clear sound and that the volume level will not result in feedback in the actual live show.
It is also at this point that presenters/performers are taught the proper microphone handling techniques to ensure a smooth live show.
Quick Fixes to Feedback During a Live Event
You have followed all the suggested ways to reduce the occurrence of microphone feedback, but still, that terrible screeching noise does occur during a live session.
Most feedback loops will occur either due to loud volume on the stage, improper microphone placement, or loudspeaker and monitor placements.
Now, let’s discuss the quick fixes to stop that annoying noisy distraction when it occurs.
3 Quick Fixes to Microphone Feedback
- Turn down the microphone
- Move the microphone
- Equalize the microphone
Turn Down the Microphone
This is by far the fastest and easiest way to fix microphone feedback especially if you are a sound technician.
Simply identify the offending microphone channel and reduce the volume.
If the loudspeaker monitors on stage are the cause of the feedback, you just need to turn down the volume in the appropriate monitor channels – just a little bit.
This volume adjustment can make a huge difference in the overall sound quality.
Move the Microphone
This is another quick fix for microphone feedback.
If you find out that the issue is the position of the microphones in relation to loudspeakers and monitors, easily correct this by moving the microphones away from the speakers.
Sometimes, the microphones placed on stands can be too far from the presenter’s mouth.
Quickly fix this by moving the mics up, closer to the mouth to provide better signals.
Equalize the Microphone
Equalization comes in if you can’t turn down the volume or move the microphones.
This process is easy if your ears are able to catch the frequency creating the feedback fast.
As a sound technician, you need to be alert always to catch feedback and correct it fast while an event is happening.
To Recap How to Fix High Pitch Noises Coming From a Microphone
Technically, feedback is a sound loop between an audio input and an audio output, in our case, a microphone and loudspeakers.
It’s caused by:
- Improper microphone and loudspeaker placement
- Loud volumes from the microphones and speakers
- Using omnidirectional microphones
- Improper microphone holding techniques by presenters
- The acoustics of an enclosed space
How To Prevent Feedback?
- Properly position microphones and loudspeakers
- Adjust the volume of microphones and speakers during soundcheck
- Use cardioid and super-cardioid types of microphones
- Train presenters on proper microphone handling techniques
- Treat the acoustics of a room
How To Fix Feedback Quickly in a Live Session
- Turn down the microphone
- Move the microphone
- Equalize the microphone
The Causal Factors of Microphone Feedback
We now know what feedback or high pitch noise is, but what really causes this?
Here are the causal factors of microphone feedback:
- The microphone is at the wrong angle in relation to the loudspeakers
- The microphone and loudspeakers are in proximity
- The microphone is far from the source of sound but close to the loudspeakers
- Wrong positioning of the loudspeakers that point directly at reflective surfaces
- The increased volume of the loudspeakers
- The increased volume of the microphone
- The number of open microphones is unlimited
- The microphone is on when not in use
- Use of speaker monitors
- Omnidirectional microphones
- The size and shape of the physical space
Microphone feedback is an equally annoying and stressful experience for the audience, presenters, performers, and sound technicians.
That terrible high pitch noise coming from your microphone can be fixed and prevented from occurring in the first place.
By practicing the suggestions in this article, eliminating microphone feedback will be easy and quick.
I hope this article helped you understand microphone feedback, its triggers, how to prevent it, and fix it if it occurs.
Have you experienced microphone feedback before?
How did you fix it?
Feel free to share your experience in the comment section below.