How to Use OBS Expander as a Strict Noise Gate

This guide provides a straightforward walkthrough on how to configure the Expander filter in OBS Studio to function as a strict noise gate. While OBS includes a dedicated Noise Gate filter, utilizing the Expander filter offers superior control over how your microphone cuts out background noise, allowing for a more natural-sounding silence without abrupt audio clipping. By adjusting key settings like ratio, threshold, and release times, you can eliminate keyboard clicks, computer fans, and ambient room noise from your stream or recording.

Step 1: Add the Expander Filter to Your Microphone

1. Open OBS Studio.
2. Locate your microphone source in the Audio Mixer dock.
3. Click the three dots (options) icon next to your microphone and select Filters.
4. Click the plus (+) icon in the bottom-left corner of the Filters window.
5. Select Expander from the list, name it (e.g., “Strict Gate Expander”), and click OK.

Step 2: Configure the Settings for a Strict Noise Gate

To force the Expander to behave like a strict noise gate, you must configure it to aggressively reduce any audio that falls below your volume threshold. Use the following settings in the filter properties:

• Preset: Set this to Gate. This automatically adjusts the default parameters to behave like a noise gate.
• Ratio: Set this to 10:1 or higher (up to 20:1). A high ratio ensures that once your voice drops below the threshold, the volume reduction is so steep that it effectively mutes the audio.
• Threshold: This is the most critical setting. Set this to a level just above your background noise but below your normal speaking voice (typically between -40 dB and -50 dB).
  • How to find your threshold: Stop speaking and watch the green bar on your OBS audio meter. Note where the background noise peaks (e.g., -55 dB). Set your threshold 3 to 5 dB higher than that peak (e.g., -50 dB).
• Attack: Set this to 2 ms (or as low as 1 ms). A fast attack time ensures the gate opens instantly the millisecond you start speaking, preventing the first syllable of your words from being cut off.
• Release: Set this to between 100 ms and 150 ms. This determines how quickly the gate closes after you stop speaking. A value in this range prevents the gate from cutting off the tail ends of your words while still closing quickly enough to block sudden background noises.
• Output Gain: Leave this at 0 dB.
• Detection: Set this to Peak. Peak detection reacts instantly to the sudden spikes of your voice, which is ideal for a strict noise gate.

Step 3: Test and Fine-Tune

After applying the settings, speak naturally into your microphone while monitoring the audio meter in OBS.

• If the gate is cutting off the beginning of your words, decrease the Threshold slider (move it to the left, e.g., from -45 dB to -50 dB).
• If background noises like keyboard typing are still triggering the microphone to open, increase the Threshold slider (move it to the right, e.g., from -45 dB to -40 dB).