How to Set Up Audio Ducking in OBS Studio

Audio ducking is a technique that automatically lowers the volume of background audio, such as music or game sound, whenever someone speaks into a microphone. This article explains what audio ducking is, why it is essential for streamers and content creators, and provides a clear, step-by-step guide on how to configure this feature in OBS Studio using the built-in Compressor filter.

What is Audio Ducking?

Audio ducking (also known as sidechain compression) is an audio processing method where the level of one audio signal is temporarily reduced by the presence of another signal. In broadcasting and streaming, it is most commonly used to lower background music or gameplay audio whenever the creator speaks.

Without audio ducking, you must manually adjust your audio levels, which often results in the background music either being too quiet during pauses or too loud and drowning out your voice. Audio ducking automates this process in real-time, ensuring your voice remains clear and intelligible without sacrificing the energy of your background audio.

How to Set Up Audio Ducking in OBS Studio

To set up audio ducking in OBS Studio, you will apply a Compressor filter to your background audio source (such as Desktop Audio or Game Audio) and link it to your microphone.

Step 1: Locate Your Audio Sources

Open OBS Studio and look at the Audio Mixer dock. Identify the two sources you will use: 1. The Controlling Source: This is your microphone (usually labeled Mic/Aux). 2. The Target Source: This is the background audio you want to quiet down (usually labeled Desktop Audio, Game Audio, or Media Source).

Step 2: Add a Compressor Filter

1. Click the three dots (Options) next to your background audio source (the target source) in the Audio Mixer.
2. Select Filters from the dropdown menu.
3. Click the plus (+) icon in the bottom-left corner of the Filters window.
4. Select Compressor from the list of filters.
5. Name the filter “Audio Ducking” or “Compressor” and click OK.

Step 3: Configure the Sidechain Source

Within the Compressor filter settings, locate the dropdown menu labeled Sidechain/Ducking Source. * Click this dropdown and select your Microphone (Mic/Aux). This tells OBS to use your voice as the trigger to lower the background audio.

Step 4: Fine-Tune the Settings

To make the audio ducking sound natural, adjust the compressor sliders using these recommended baseline settings:

• Ratio: Set this between 2.5:1 and 4:1. This determines how much the background audio is reduced. A higher ratio means the background audio will become quieter when you speak.
• Threshold: Set this between -30 dB and -40 dB. This dictates the microphone volume level required to trigger the ducking. If the ducking doesn’t activate when you speak normally, raise the threshold (move the slider to the right). If it activates from background noise, lower the threshold.
• Attack: Set this between 50 ms and 100 ms. This controls how quickly the background audio volume drops when you start speaking. A fast attack ensures your first words are not drowned out.
• Release: Set this between 500 ms and 700 ms. This controls how quickly the background audio returns to its original volume after you stop speaking. A moderate release prevents the audio from bouncing back too quickly during brief pauses between words.
• Output Gain: Leave this at 0 dB. You do not need to boost the output level for audio ducking.

Step 5: Test and Adjust

Close the filter window and speak into your microphone while background audio is playing. Watch the volume meters in the Audio Mixer. You should see the green bar for your background audio visibly drop whenever you talk, and smoothly rise back to its original level when you are silent. Adjust the Threshold and Ratio sliders as needed until the balance sounds natural to your ears.