The Case for Noise Reduction
For the last 10+ years, I’ve been producing video training materials on IT systems automation, cloud, containers, and software development. Over the course of these years, I’ve learned many techniques about how to improve both video and audio quality. In fact, I wrote an article about key techniques to produce a great video. One of the techniques I’ve picked up more recently is noise reduction.
No matter what type of microphone you’re using, there were always be background noise. This is well-known as the “self-noise” of a microphone. There are other types of noise besides the internal electronic noise, however.
As a listener, you don’t always realize the amount of effort that goes into producing high quality audio. Listeners hear background noises, wet-mouth, and heavy breathing, but otherwise expect a crisp listening experience.
Some common examples of background noises include:
- The constant hum of a fan
- Wind whipping against the window
- Cars driving past the house or office
- Birds chirping outside
- Air blowing through HVAC vents
For the past several months, I have been using Open Broadcaster Studio (OBS), to create video recordings. OBS offers a variety of built-in filters for both audio and video streams. These built-in filters include a “Noise Reduction” filter. However, the built-in noise reduction plug-in only does a so-so job.
A Working Noise Reduction Solution
What can we do to solve this problem?
There’s a professional digital audio workstation (DAW) package called REAPER. REAPER itself has a license cost, but the company offers a free plug-in set. ReaPlugs are built on the standard Virtual Studio Technology (VST) interface, which processes audio in the pipeline.
For now, go ahead and download ReaPlugs and install the package on your system. OBS should automatically pick up these plug-ins when you add a VST filter.
One of the VST plug-ins included in ReaPlugs is called ReaFIR. ReaFIR lets you record a noise profile and then apply it in real-time. In fact, you can add the plug-in to your audio filters multiple times, and pre-record different noise profiles. That way, depending on what noises are in your environment, you can enable or disable them at will.
Add ReaFIR to your audio input
Now let’s add the ReaFIR plug-in to your OBS configuration.
Right-click your audio input in OBS and select the Filters option. On the bottom-left of the Filters screen, click the plus sign. Choose the VST 2.x Plug-in option.
- You can type any desired name for the plug-in, such as “Box Fan Noise Reduction”
- From the drop-down box, select the reafir_standalone plug-in
- Click the Open Plug-in Interface button to configure ReaFIR
- From the Mode drop-down, choose Subtract
- Check the box Automatically build noise profile
- Let the background noise build the profile for a few seconds
- Uncheck the box and close the window. You’re done!
Now that you’ve completed the configuration of ReaFIR, give it a try. Recording a new video clip and see how well the noise reduction works. You should notice a significant improvement in the clarity of your voice!
Example Noise Reduction Profiles
Now that you understand how to solve noise reduction, let’s explore some common examples of noise profiles.
Although I prefer having a silent desktop computer, a high-performance computer will generate heat. Between the CPU and GPU fans, my media production machine creates a little noise. The red line indicates the noise profile that is built by ReaFIR.
I have a box fan that I sometimes use to eject heat from my office. This is a fairly inexpensive, noisy, yet effective unit. The box fan’s noise profile covers a much wider frequency range than the desktop computer fan. Although the highest decibel level is around 100Hz, it ranges all the way up to 10kHz.
Although every keyboard will have a unique noise profile, I’m using the Microsoft Sidewinder X4. While typing a few words, this is what its noise profile looks like. As you can see, the high points are around 45Hz and a range from 400Hz to 10kHz.
By using the techniques in this article, you should notice a drastic benefit to your audio quality. I hope this helped you to understand how to employ noise reduction in OBS. Please check out some of the articles on my website, and leave a comment with your feedback!