OBS Audio Latency: Fix Sync Issues for Streaming

Your OBS stream looks perfect on your PC, but viewers are telling you the audio is out of sync. Your character’s mouth moves a second before you hear the dialogue. Or worse, every few minutes the audio drifts further out of sync. OBS itself isn’t the problem—it’s usually a mismatch between your audio sources, mismatched sample rates, or a capture device introducing delay that OBS isn’t compensating for.

The good news: OBS has built-in tools to fix this. You just need to know where to look and what to adjust.

Constant vs. Gradual Audio Drift

Before you start tweaking, identify which problem you have:

Constant Latency

Your audio is consistently ahead of or behind the video by the same amount from start to finish. This is fixable with Sync Offset.

Gradual Drift

Audio starts in sync but slowly gets more out of sync over 10+ minutes. This usually means sample rate mismatch or USB bandwidth contention.

Fix them differently.

Fixing Constant Audio Latency

Step 1: Identify Which Audio Source Is Late

Record a short test clip (30 seconds) with all your audio sources: microphone, desktop audio, game capture, etc. Play it back frame-by-frame and find the moment your hands clap or you speak. Compare that moment to when the audio waveform spikes. If audio spikes before your hands meet, audio is ahead. If it spikes after, audio is behind.

Step 2: Open Advanced Audio Properties

In OBS:

1. Click the Audio Mixer panel (usually bottom of the screen).
2. Find the gear icon next to any audio source.
3. Click it and select “Advanced Audio Properties.”

A window opens showing all your active audio sources in a table. You’ll see columns for “Sync Offset (ms)” which is what you’re after.

Step 3: Apply Sync Offset

If your audio is ahead of the video by, say, 150ms, enter “150” in the Sync Offset column for that audio source. This delays the audio so it catches up to the video. Positive values add delay (audio waits); negative values pull audio earlier (rarely needed).

Common Starting Points:

• USB microphone or headset: Start at 50ms
• Capture card audio: Start at 100–200ms
• Desktop audio (game, browser): Start at 50–100ms
• Bluetooth headset: Start at 200–300ms (though Bluetooth timing is often inconsistent)

Step 4: Test and Fine-Tune

Apply the offset, record a 10-second test, and check frame-by-frame again. If you’re closer but not perfect, adjust in 10–20ms increments. Once you find the sweet spot, the offset is saved to that source in your OBS profile.

Fixing Gradual Audio Drift

Gradual drift is almost always sample rate mismatch.

Step 1: Check Your Audio Device Sample Rates

Your audio interface, microphone, and desktop audio might be running at different sample rates. OBS tries to resample everything to a standard rate (usually 48kHz), but if devices don’t match, audio slowly drifts.

Open your OS audio settings:

Windows: Right-click the speaker icon in the system tray > Sound settings > Advanced > App volume and device preferences. Check the sample rate for each device. They should all be 48kHz.

Mac: System Preferences > Sound > Output tab. Note the sample rate. Repeat for Input.

Linux: Run pactl info or check PulseAudio settings. Confirm 48kHz is the default.

Step 2: Set All Devices to 48kHz

Most modern devices default to 48kHz, but some are stuck on 44.1kHz. Change your audio interface, USB mic, or headset to 48kHz in their control panel or OS settings.

Mismatched sample rates cause gradual drift because one device is technically running slightly faster than another. Over a 30-minute stream, the gap widens noticeably.

Step 3: Confirm OBS Is Set to 48kHz

In OBS:

1. Settings > Audio.
2. Check the “Sample Rate” dropdown. It should be 48kHz.

If OBS is set to 44.1kHz and your capture card is sending 48kHz, OBS resamples constantly, introducing tiny timing errors that accumulate.

Handling Audio Monitoring Latency

OBS’s audio monitoring (hearing yourself through OBS while you stream) adds latency. If you’re monitoring your mic through OBS and it feels delayed:

Option 1: Use Hardware Monitoring

If your audio interface supports direct hardware monitoring, use it instead. Your interface loops the mic signal straight back to your headphones with zero software delay. In OBS, set that audio source’s “Audio Monitoring” to “Monitor Off” so you’re not double-monitoring.

Option 2: Use a Virtual Cable

Tools like VB-Audio Virtual Cable (Windows) or Soundflower (Mac) let you route audio outside OBS for monitoring with less delay. This is an advanced workaround—use hardware monitoring if available.

Fixing Audio That’s Ahead of Video

Audio is typically ahead of video with capture cards. You hear the dialogue before the character’s lips move.

In Advanced Audio Properties, apply a positive Sync Offset (e.g., 100ms) to delay that audio source. This is the most common fix.

Fixing Audio That’s Behind Video

Audio lags behind the video. Your character’s lips move, then you hear the dialogue.

Apply a negative Sync Offset (e.g., -50ms). Negative values pull audio earlier relative to video. This is less common and usually indicates a USB microphone or interface with inherent delay. Confirm your interface drivers are up-to-date first—outdated drivers sometimes cause this.

When Multiple Audio Sources Have Different Latencies

If you’re streaming with a capture card (120ms latency) and a USB mic (50ms latency), set them individually:

• Capture card audio source: Sync Offset = 120ms
• USB mic source: Sync Offset = 50ms

Both stay synced to the video and to each other. If you applied a single global offset, one would be ahead again.

Using Global Audio Sync Offset

If all your audio sources have the same latency (e.g., everything is 80ms ahead), you can set it globally instead of per-source:

1. Settings > Audio.
2. Scroll down to “Global Audio Sync Offset (ms).”
3. Enter the delay.

This is faster if your entire setup has uniform latency. But if you have mixed devices, sync them individually in Advanced Audio Properties.

Checking Your OBS Sample Rate vs. Device Sample Rate

Mismatched sample rates cause gradual drift. Here’s how to verify:

1. Open OBS Settings > Audio.
2. Note the “Sample Rate.” It’s usually 48kHz.
3. In Windows Sound Settings (or Mac Audio preferences), check your microphone and system audio sample rate. They should match OBS.

If your mic is 44.1kHz and OBS is 48kHz, OBS will resample, and over time the timing drifts.

Advanced: Using a Delay Filter

If Advanced Audio Properties isn’t working (older OBS versions), you can apply a delay filter:

1. Right-click an audio source in the mixer.
2. Click “Filters.”
3. Click the “+” icon and select “Delay (Async).”
4. Set the delay in milliseconds.

This works the same way as Sync Offset but as a filter stack instead of a built-in property.

Testing Before You Stream

Always do a local recording first:

1. File > Start Recording.
2. Play your game, speak into your mic, do everything you’d do live.
3. Record for at least 5 minutes (longer catches gradual drift).
4. Stop recording.
5. Play back the file and check sync frame-by-frame.

Once local recording is locked, your stream preview and live broadcast should be in sync. The platform delay (Twitch/YouTube buffering) adds extra delay that viewers experience, but that’s not OBS’s problem.

Quick OBS Audio Sync Checklist

• [ ] Record a test clip and check which audio source is out of sync
• [ ] Open Advanced Audio Properties
• [ ] Apply Sync Offset to that source (start at 50–200ms)
• [ ] Re-test and fine-tune in 10–20ms increments
• [ ] Confirm all audio devices are set to 48kHz
• [ ] Confirm OBS is set to 48kHz
• [ ] Check that sample rates match between OBS, your mic, your interface, and your capture card
• [ ] Disable audio monitoring on sources where you’re using hardware monitoring instead
• [ ] Do a 5+ minute local recording test before streaming live

When Nothing Works

If you’ve matched sample rates, set Sync Offset, and audio still drifts:

1. Update your audio drivers (mic, interface, capture card).
2. Move your capture card to its own USB 3.0 port (not a hub).
3. Close unnecessary background apps eating CPU.
4. Try a different USB cable or port.
5. Restart OBS and your audio devices.

These steps often uncover USB or driver issues that cause unpredictable latency.

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