How to Reduce Microphone Background Noise [with Blue Yeti examples]
In this article, I’ll demonstrate how to decrease background noise from your microphone with several examples including the Blue Yeti. To specifically reduce the static hiss of a mic, scroll down to the final solution.
Short Answer
The main ways to reduce background noise are:
keeping the recording space as quiet as possible
using a dynamic microphone
using the correct polar pattern
positioning the mic properly with a boom arm
using a software noise reduction filter
Explanation
Noise is considered any type of sound introduced into a recording that is not the intended sound source.
There are two main types of noise to consider when recording audio: ambient noise and noise floor.
Noise Types
Ambient noise
Ambient noise refers to sounds from around the recording space that are picked up by the mic. Examples are cars driving by, a computer fan, flourecent lights, or a nearby refridgerator. As I’ll explain, some mics are more sensitive to background noise than others. The Blue Yeti is one of the most sensitive mics to ambient noise.
PC fans from a CPU cooler, GPU, and power supply all create ambient noise.
Noise floor
Noise floor is the TV-static sounding hiss that is present in all microphones and audio interfaces. The volume varies drastically amongst different devices.
The Razer Seiren Elite has a loud self-noise AKA noise floor.
Continuous vs incidental sound
With both ambient noise and noise floor, the sounds can be categorized into continuous or incidental sounds. Continuous or recurring sounds like fans and flourecent lights are easier to eliminate with a software filter, and incidental sounds like bumping the mic or keyboard typing are harder to remove.
Noise floor from mics and audio interfaces is generally a continous sound.
Solutions
Here are five main ways to reduce background noise: creating a quiet recording space, using a dynamic microphone, using a cardioid polar pattern, positioning the mic properly with a boom arm, and using a software noise reduction filter.
1) Create a quiet recording space
Creating a quiet recording space is simple, but it can be difficult to pull of in a home environment. Sounds that you might not think about like fluorescent lights or a laundry room dryer should be shut off if possible.
In a studio booth, the room is mostly silent and acoustically dead with padding on the walls and usually the ceiling. The padding reduces echo, but not so much noise from outside the room. This is the ideal scenario for recording audio.
However, for those creating content from home, sounds from inside or outside a room can leak in. In my case, I can’t control when someone wants to mow their lawn. I also can’t turn down the fan on my computer’s power supply unit.
So get your recording space as quiet as you can, but if there’s not a lot you can control, there are still several more techniques we can apply.
2) Use a dynamic microphone
Two dynamic microphones, the Razer Seiren Elite and Samson Q2U.
The HyperX QuadCast and Blue Yeti are condenser microphones.
Dynamic microphones are generally less sensitive to ambient sounds due to the design of the capsule. Unlike condenser capsules which require a constant charge of energy or “phantom power”, dynamic microphones have their coil moved by sound waves themselves. Softer sounds move the coil a lot less.
This background noise rejection makes dynamic microphones ideal for podcasting and streaming in home environments. Some popular dynamic microphones are the Samson Q2U and the Shure SM7B. The Razer Seiren Elite that I’ve used to demonstrate also has a built-in high pass filter to further eliminate rumbles from typing.
3) Use the correct polar pattern
Polar pattern knobs on the back of the Blue Yeti and HyperX QuadCast.
A polar pattern describes the sensitivity of a microphone to sounds in different directions. For example, the Blue Yeti and HyperX Quadcast have 4 different polar patterns. On these two mics, the 3rd option is cardioid which is best for reducing background noise.
Most microphones only record in cardioid, and in most scenarios that is the preferred polar pattern to emphasize your voice and pick up as little ambient noise as possible.
4) Position the mic properly with a boom arm
Boom arms allow you to place the mic closer to the sound source and off of the flat surface of your desk. This optimized distance will improve the sound quality and also decrease keyboards sounds - both the high end clacking and low end rumble from the desk vibrating.
5) Use a software noise reduction filter
When the previous options aren’t enough to eliminate background noise, using a software filter should finish things off. This is the simplest way to deal with a loud noise floor and subtle fan noises. Four common noise reduction filters are:
OBS noise supression filter
Audacity noise reduction filter
Krisp.ai (freemium)
NVIDIA RTX Voice (Requires NVIDIA graphics card)
The first two are less aggressive and generally keep your main sound source intact. Krisp and RTX Voice are more effective at removing louder noises, but they can negatively alter the overall tone of your audio.
OBS noise suppression RNNoise
OBS (Open Broadcaster Software Studio) is a free, popular program used for streaming and recording video. Built into OBS are several basic audio filters. RNNoise is tuned to decrease the volume of continuous background sounds like computer fans and noise floor rather than incidental sounds. Here’s how to reduce background noise with RNNoise in OBS:
first click the gear icon next to your audio source and click filters.
then click the “+” to add a new audio filter and select “Noise Suppression”. In method, click RNNoise.
To toggle the filter on or off, click the eye icon next to the filter you just added on the left.
Click the gear next to your mic and click filters.
Click the + sign and click noise suppression.
Select RNNoise. Toggle it on and off with the eye icon.
Audacity Noise Reduction
Here’s how to use Audacity’s noise reduction filter:
Import your audio into Audacity
Highlight a section with no vocals or instrumentals (just the noise you want to remove)
Click Effects at the top and click Noise Reduction
Click Get Noise Profile
Highlight the entire track (ctrl+A)
Click Effects > Noise Reduction > OK.
You can alter the settings in the Noise Reduction window to change the sensitivity and how many dB you want the sound lowered. After applying the effect, you’ll be able to see a difference in the waveform.
Krisp.ai Noise Concellation App
Krisp is a noise cancellation app that can be downloaded from krisp.ai. It reduces background noise from whatever mic you are using and it creates a virtual microphone source that you can use in other programs. Zoom, OBS, Audacity and pretty much any program that can use a microphone is compatible with Krisp.
Here’s how to use Krisp:
Download the app from krisp.ai.
Select your microphone in the Krisp setup menu.
Select Krisp as your audio source in the program you want to record or video conference with.
Download program from Krisp.ai. Signup only requires an email.
Select the mic you want to remove noise from.
Select Krisp in your audio program of choice.
Personally, I find Krisp to be a last resort method. I will elaborate on Krisp specifically in another article, but the noise reduction is very aggressive which can distort your voice. I also find the app a bit intrusive. Lastly, Krisp is a freemium program, so you are limited in its usage unless you pay money.
NVIDIA RTX Voice
NVIDIA RTX Voice is another noise cancellation software. This one is exclusive to NVIDIA graphics cards. Previously it only worked with RTX cards, but it has been updated to be compatible with all GeForce, Quadro, TITAN, and RTX cards. The example graphics card on my laptop is a GTX 960M. Here’s how to use RTX Voice:
Download the software from NVIDIA’s website.
Select the mic you want to remove sound from and tick the box.
Adjust the slider to change the noise suppression level.
Add RTX Voice as your sound souce in your audio recording program of choice.
Download RTX Voice or NVIDIA Broadcast depending on which graphics card you have.
Configure your mic in the RTX Voice window.
Select RTX Voice in your software of choosing.
I’ll be doing a thorough review of RTX voice in another article. But briefly, I like RTX voice better overall than Krisp and would recommend it if you have the option. Having a noise suppression slider is good, and overall it had a less noticeable effect on my actual voice.
Still, if you want your primary audio source mostly intact, I suggest using a less aggressive noise reduction filter like OBS’s RNNoise or manually removing the noise in Audacity.
