Do not get Noise Suppression confused with a Noise Gate. They are very different concepts. A noise gate cuts off all noise until a threshold is reached, then it opens. Noise suppression only cuts down certain frequencies of noise. For ease of understanding, you can consider that range to be ambient air sounds, when no one is speaking, no wind, etc. Sit in your room, don’t talk, and just listen. The silence, ambient noise, is the noise we want to minimize.
Practical Application
The noise suppression is useful for cleaning up your audio and cutting the constant air sound in your mic while streaming. Different noise suppression plugins have varying options. If you are using the basic plugin inside of OBS then suppression level is your only setting.
Suppression Level
OBS automatically determines the noise it needs to cut. The suppression level tells OBS how much to reduce the “noise” by. 0 dB is off. -10 dB starts reducing the noise.
A Word of Caution
Remember Charlie Brown’s teacher? “Whahm, wahm, wah, wah… wah wah wah wah.” That’s what you’ll sound like if you aren’t careful with noise suppression. Start low. -10 dB. Listen. If you hear a hum you don’t like, cut it a little more. It’s okay to have some noise provided it’s not a high pitched noise. High pitched noises generally indicate a different audio issue.
Conclusion
We hear ambient noise all day every day. However, when we are streaming a podcast or video games, we want clearer, cleaner sound.