> ## Documentation Index
> Fetch the complete documentation index at: https://www.tella.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# How to fix audio sync for XLR microphones

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If you’re using an XLR microphone (like the Shure SM7B) with Tella and noticing your audio is slightly *ahead* of your video, don’t worry — it’s easy to fix.

This guide walks you through setting up two small apps to sync your audio perfectly with your video recordings.

### Why does audio desync happen?

XLR microphones process and deliver audio to your computer faster than your camera delivers video.

Typically, the audio arrives about **100 milliseconds** earlier.

To fix this, we’ll add a small delay to the mic audio before it reaches Tella.

### What you’ll need

You’ll need two apps made by Rogue Amoeba:

* Audio Hijack – to add a delay to your microphone input

* Loopback – to create a “virtual microphone” that you can select in Tella

Both offer free trials, but you’ll need licenses for long-term use.

### Step 1: Install Audio Hijack and Loopback

1. Download and install **Audio Hijack** and **Loopback** from Rogue Amoeba.

2. Open both apps — we’ll set them up next.

### Step 2: Set up Audio Hijack

1. **Create a New Session** in Audio Hijack.

2. **Add an Input Device Block**:

   * Choose your **audio interface** as the input (e.g., Scarlett 2i2, Apollo Solo, etc.).

   * Remember: you’re selecting the **interface**, not the mic itself.

3. **Add a Sync (Delay) Block**:

   * Drag in the Sync block.

   * Set the delay to **-100 milliseconds**.

   * This slows down your mic to match your camera timing.

4. **Add an Output Device Block**:

   * You’ll connect this to your virtual mic (set up in Step 3).

### Step 3: Set up Loopback

1. **Create a New Virtual Device** in Loopback.

2. Name it something like **“Shure SM7B Sync”** or **“Tella Mic”**.

3. Leave the default settings — it just needs to pass the delayed audio through.

### Step 4: Connect Audio Hijack to Loopback

1. In Audio Hijack, for the Output Device, select the **new virtual mic** you created in Loopback.

2. Run the session.

   * You should see the audio flowing through the delay and into the virtual mic.

### Step 5: Select your virtual mic in Tella

When recording in Tella (or Zoom, Google Meet, etc.):

* Choose your new virtual microphone (e.g., **“Tella Mic”**) from the audio input options.

Your audio and video should now be perfectly in sync!

### Quick troubleshooting

* **Audio still slightly off?**

  Adjust the delay slightly (e.g., try -90ms or -110ms) in Audio Hijack.

* **Apps need to stay open**:

  Make sure Audio Hijack and Loopback are running in the background while recording.

### Summary

1. Install Audio Hijack and Loopback

2. Add a 100ms delay in Audio Hijack

3. Route the delayed audio into a virtual mic with Loopback

4. Select the virtual mic in Tella

5. Record perfectly synced videos!