Microphone feedback is one of the most unpleasant sounds we’ll encounter in the world of audio. Though mic feedback is most often heard in live sound reinforcement situations, it can easily happen on your computer, too.
Here are step-by-step instructions to stop a microphone feedback loop in a computer:
- Mute the output immediately
- Figure out the audio input device and audio output device used by the computer
- Switch and/or adjust the devices as necessary
- Drop the input gain to zero, then Unmute and adjust the output volume to the intended level
- Slowly increase the input gain
In this article, we'll get into each of these 5 steps with more details to stop the microphone feedback loops in your computer for good!
What Causes Audio Feedback In A Computer?
Let's begin by stating that computers will not typically create audio feedback loops when left to default settings. By default, the computer's audio input is not being routed immediately to the computer's audio output.
It is only when the computer's audio output directly monitors its audio input that feedback can happen.
However, when the computer's audio output is in close proximity to its audio input, there is the potential for feedback issues.
For example, a computer's built-in speakers and built-in microphones are both within the same physical unit.
Therefore, monitoring the built-in mic with the built-in speakers may very well cause an audio feedback loop. Similarly, if you're using an audio interface with your computer, pointing the live microphone at the speaker monitor is a recipe for feedback.
Under normal default circumstances, computers do not monitor their built-in microphones with their built-in speakers, so there is little to worry about. The potential for feedback really starts happening when we start routing the audio within the computer.
1. Mute The Output Immediately
If you start to hear feedback, it's critical to lower the offending audio channels immediately before it gets worse. The easiest way to do this on a computer is to mute the output.
In a laptop, this should be as simple as hitting the mute button (assuming that the computer's built-in speakers are set as the audio output device).
If you're using an audio interface, mute the interface's output to your speakers/monitors. Alternatively, you could quickly turn down the output level of the audio interface (especially if the interface does not have a mute button).
As a third option (though this isn't truly muting), try turning off your speakers/monitors, so that sound (and feedback) stops coming out of them.
It's not good practice to unplug equipment while it's on or to turn off equipment between an audio input and output. Therefore, I wouldn't recommend turning off the interface (between the computer and speakers/monitors). However, this would likely solve the feedback problem.
If we really think about it, this single step of muting the computer audio output is all we need to do to stop the feedback loop in the computer. That being said, it's important to know how to solve the issue so that we may resume our audio work.
2. Figure Out The Audio Input Device And Audio Output Device Used By The Computer
The next step in solving the computer audio feedback problem is knowing the audio inputs and outputs of the computer.
For example, if a laptop's audio input is its built-in microphone and its audio output is its built-in speakers, we may have a problem. At a certain mic gain and/or speaker volume, the mic will pick up its own signal as sound from the speakers and cause a feedback loop.
Similarly, let's say the computer's input audio device is an audio interface with a microphone plugged into it, and its output device is the interface with a set of studio monitors. If the microphone has a lot of gain and is pointed at the turned-up monitors, there's a high chance of a feedback loop occurring.
For more information on using audio interfaces, microphones and speakers with computers, check out my articles:
• How To Connect A Microphone To A Computer (A Detailed Guide)
• How To Connect Speakers To A Computer (All Speaker Types)
The point here is, if we know our computer's audio input and output devices, we can take the necessary steps to ensure that no feedback takes place in the audio/sound.
To figure out the audio input device on Mac OS, follow this path:
- System Preferences
To figure out the audio output device on Mac OS, follow this path:
- System Preferences
To figure out the audio input device on Windows OS, follow this path:
- Control Panel
To figure out the audio output device on Windows OS, follow this path:
- Control Panel
3. Switch And/Or Adjust The Devices As Necessary
Once in the menu, it's important to choose the proper audio input and output devices.
For example, if you're using the built-in mic as the input, try to use the headphone output to monitor rather than the built-in speakers.
Another example could be that if you're using an audio interface and have a live microphone and studio monitors, ensure that they are positioned in a way that is not conducive to audio feedback. In many studios, this means having the monitors in a control room and the microphones in a separate live room.
The takeaway here is to set up the audio input and output so that feedback is not likely to happen.
4. Drop The Input Gain To Zero And Adjust The Output Volume To The Intended Level
Of course, if an output directly monitors an input in the same acoustic space, there's always a chance for audio feedback.
Though this isn't the method everyone uses, it's an effective method for gauging gain-before-feedback.
Once the inputs and outputs are set, drop the gain of the input to zero. Unmute and set your output (speaker monitors, headphones, etc.) to the level you typically operate them at.
5. Slowly Increase The Input Gain
Slowly increase the input gain (of the built-in or external microphone) to a healthy level or until feedback begins to occur.
If feedback happens before you get to a healthy level, try repositioning the input/output devices or, better yet, change the output to the headphones out. Closed headphones can help you to better monitor the microphone without sending great amounts of sound to the microphone.
To learn more about microphone gain, check out my article What Is Microphone Gain And How Does It Affect Mic Signals?
How do you reduce feedback in a lapel/lavalier mic? To reduce feedback in a lav microphone during a live presentation with sound reinforcement, try distancing the lav wearer from the monitors and PA speakers and point the speakers away from the lav wearer. Use cardioid lav mics for more gain-before-feedback and ride levels accordingly.
How do I reduce microphone noise? There are plenty of methods to reduce noise in a microphone. Some common methods include:
- Using Clean Preamps.
- Not Running Mic Cables Alongside Power Cables.
- Recording In Quiet Soundproof Environments.
- Placing Mics Closer To The Sound Source.
- High-Pass Filtering The Mic Signal.
For a detailed guide to reducing microphone noise, check out my article 15 Ways To Effectively Reduce Microphone Noise.
Choosing the right microphone(s) for your applications and budget can be a challenging task. For this reason, I've created My New Microphone's Comprehensive Microphone Buyer's Guide. Check it out for help in determining your next microphone purchase.