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The OBS Compressor filter – Why it’s essential for streamers

Ever have somebody tell you that your mic sounds off, robotic, or that some sounds have a buzz? Of course, an untrained ear probably wouldn’t be able to actually realize that this is a problem they can solve, as individuals typically attribute it to some hardware flaw that they have no control over. In this case, though, the issue you are running into is known as “Peaking”, or “clipping”, and you totally can do something about it. This issue is one that plagues the ignorant, and those unfortunate enough to be stuck with low-end microphones attached to headphones, earbuds, phones, and many other devices. For a streamer, this kind of issue is a high priority to avoid. But how do you avoid this issue if you are stuck with the same hardware? The answer, at least if you use OBS, is the OBS Compressor filter.

For those who would prefer to have an audio reference of what to look for, take a listen to this audio clip I recorded. Just be aware, headphone users; I’m intentionally peaking the mic, and it may be loud.

Example showing what peaking is, what the compressor helps to alleviate.

The audio buzz you hear with the peaking example is the issue you are looking to resolve, and what the compressor aims to alleviate.

Here is the same clip, this time run though the compressor with extremely aggressive settings.

Note that it is not a perfect solution, as if you were to peak your actual microphone diaphragm, then no software in the world can fix it. For example, the word “This” peaked the diaphragm, meaning it vibrated beyond its capability, and the data simply isn’t there.

How the OBS Compressor filter works

Showing the components of the OBS compressor filter

A compressor is a wonderful piece of audio mastering technology used every day by music producers, audio engineers, voice actors, and yes, even streamers. Pretty much any profession that utilizes professional class audio will at one point discover the existence of audio filters and processing, and will never go back once they do.

How it works, is actually pretty simple.

You have two main values for a compressor to work:

  • The Threshold,
  • and the amount, or Ratio.

What is the Threshold?

What the threshold determines is the point at which the compressor actually turns on. Until this value is reached, it is actually completely inert and does not affect your audio signal in any way.

However, once that value, that threshold is met, things will start to happen. Your audio signal will be “turned down” to attempt to moderate the volume of the signal.

Well, I say volume, but it actually works on the dB (Decibels) scale. A Decibel is a ratio measurement typically based off of absolute silence. It is logarithmic in nature, so a 10dB sound is 100x louder than a 1dB sound.

Side note, physics allows the creation of a black hole with a loud enough sound. How loud? 1,100dB. Neat.

What is the Ratio?

The ratio is the amount it will reduce the signal by.

For example, say you had a ratio of 10:1.

What this means, is that for every 10dB you go over the threshold, the resulting signal will be reduced in volume by 1dB.

The lower your ratio, the more “aggressive” you are compressing. Remember, this scale is logarithmic in nature. Aggressive numbers are blunt instruments and are extremely noticeable to listeners who are paying close attention to the audio.

For voice compression, you actually want something along the lines of 6:1 or 4:1 or even something like two separate compressors at 12:1 and 10:1 to bring it down in steps. This gives you a bit more control over the signal, and you can actually get better results when splitting your compressor into multiple stages. However, this does result in higher processing overhead.

What about “attack”, “release”, “Output Gain”, and “Sidechain/ducking”?

These values are less important than the Threshold and Ratio, but they still help in increasing or reducing the subtlety of the filter to make it less obvious to your audience.

The Attack will determine the “fade in” effect of the compressor, or how fast it ramps up to enact its full volume reduction capability.

The Release will determine the “Fade out” effect, or how long the compressor will remain in full effect before fading back to the original volume.

As for the Output Gain, think of that as a mic booster or reducer. The gain setting will determine the initial volume that the compressor returns to. Ideally, this should be zero unless you have no other way of becoming audible to your audience.

Finally, Sidechain, or ducking, will allow you to select an audio signal for your compressor to listen to and will affect that signal as well. The sidechain source is used to monitor a problematic audio signal and will enact the compressor to suppress the audio volume when input is detected from that source. This ensures the overall sound output isn’t drowning out your voice, for example.

Why you need the OBS Compressor filter or equivalent VST filter

Look, everybody can get a little angry, or a little too excited sometimes after winning or losing an intense game, and that’s okay! Unfortunately, that burst of emotion tends to manifest as a much louder than usual exasperation. With the OBS compressor filter in the audio processing chain, you can moderate these emotional outbursts so that your audience doesn’t have to get slammed with the audio artifacts that result from peaking.

It is quite literally a “Set and forget” thing, and can make a big difference in your perceived production value as a streamer. It takes less than ten minutes to set up, and even less once you are familiar with the process. The part that takes the most time is the attack and release values.

Mentioning VST, there are special plugins that OBS has support for. These plugins also do the same thing as the filters built into OBS. However, they tend to have a few key advantages over the built-in filters:

  • They can be less resource intensive
  • and they can come with presets, making initial setup very quick.

You can learn more about these in an article I wrote a while back if you’re curious. The best part? The ones covered are free.

Thanks for reading! I’ll be covering the OBS Expander filter in a later article. When it’s finished, I’ll update this one to link it up for your convenience!

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