> ## Documentation Index
> Fetch the complete documentation index at: https://blackbox.dasha.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Filter Background Noise from Calls

> Remove background noise from call audio using Krisp-powered noise suppression. Improve speech recognition accuracy and call quality in noisy environments.

Filter out background noise from incoming audio so your agent hears speech clearly — even when callers are in noisy environments. Uses Krisp's AI-powered noise suppression engine.

**What you'll learn:** How to enable noise suppression, configure suppression levels, and choose recording strategies.

<Note>
  Krisp noise suppression incurs an additional per-minute fee.
</Note>

***

## When to use noise suppression

| Environment             | Without suppression                                    | With suppression               |
| ----------------------- | ------------------------------------------------------ | ------------------------------ |
| **Street/traffic**      | Agent mishears words, frequent "could you repeat that" | Clear speech isolation         |
| **Cafe/restaurant**     | Background chatter confuses STT                        | Voice stands out from ambiance |
| **Construction site**   | Heavy machinery drowns out caller                      | Speech remains intelligible    |
| **Home with kids/pets** | Barking, crying triggers false transcriptions          | Focuses on primary speaker     |

Noise suppression improves speech-to-text accuracy by removing non-voice audio before it reaches the transcription engine.

***

## Configure noise suppression

<Tabs>
  <Tab title="Dashboard">
    1. Open your agent's configuration
    2. Navigate to the **Features** tab
    3. Find **Noise Suppression** and toggle it on
    4. Select **Krisp** as the engine
    5. Adjust the suppression level (0–100)
    6. Choose recording strategy (raw or cleaned)
    7. Save your agent
  </Tab>

  <Tab title="API">
    ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
    const response = await fetch('https://blackbox.dasha.ai/api/v1/agents', {
      method: 'POST',
      headers: {
        'Authorization': 'Bearer YOUR_API_KEY',
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({
        name: 'Support Agent',
        config: {
          features: {
            noiseSuppression: {
              isEnabled: true,
              type: 'krisp',
              noiseSuppressionLevel: 75,
              recordWriteStrategy: 'raw'
            }
          }
          // ... other config
        }
      })
    });
    ```
  </Tab>
</Tabs>

***

## Configuration options

| Field                   | Type    | Default  | Description                          |
| ----------------------- | ------- | -------- | ------------------------------------ |
| `isEnabled`             | boolean | `false`  | Master toggle for noise suppression  |
| `type`                  | string  | `"none"` | Engine: `"none"` or `"krisp"`        |
| `noiseSuppressionLevel` | integer | `75`     | Aggressiveness (0–100)               |
| `recordWriteStrategy`   | string  | `"raw"`  | What to save: `"raw"` or `"cleaned"` |

***

## Suppression levels

The `noiseSuppressionLevel` controls how aggressively background noise is filtered:

| Level      | Effect             | Best for                                 |
| ---------- | ------------------ | ---------------------------------------- |
| **0–30**   | Light filtering    | Quiet environments with occasional noise |
| **40–60**  | Moderate filtering | Office or home settings                  |
| **70–85**  | Strong filtering   | Busy public spaces (default: 75)         |
| **90–100** | Maximum filtering  | Extremely noisy environments             |

<Warning>
  Very high levels (90+) may slightly affect voice quality. Start at 75 and adjust based on your use case.
</Warning>

***

## Recording strategy

Choose what audio gets saved in call recordings:

| Strategy    | Saves                      | Use when                                                    |
| ----------- | -------------------------- | ----------------------------------------------------------- |
| **raw**     | Original unprocessed audio | You need the authentic recording for compliance or disputes |
| **cleaned** | Noise-suppressed audio     | You want cleaner recordings for review or training          |

<Accordion title="Example: Compliance-first (raw recordings)">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  noiseSuppression: {
    isEnabled: true,
    type: 'krisp',
    noiseSuppressionLevel: 75,
    recordWriteStrategy: 'raw'  // Keep original audio for legal purposes
  }
  ```
</Accordion>

<Accordion title="Example: Clean recordings for QA">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  noiseSuppression: {
    isEnabled: true,
    type: 'krisp',
    noiseSuppressionLevel: 80,
    recordWriteStrategy: 'cleaned'  // Save the cleaned version
  }
  ```
</Accordion>

***

## How it works

1. **Caller audio arrives** with background noise
2. **Krisp engine processes** the audio in real-time
3. **Cleaned audio goes to STT** for accurate transcription
4. **Recording saves** either raw or cleaned audio (your choice)

The agent always hears the cleaned audio. The recording strategy only affects what gets stored.

***

## Troubleshooting

### Agent still mishearing in noisy environments

| Symptom                                | Fix                                             |
| -------------------------------------- | ----------------------------------------------- |
| Suppression enabled but no improvement | Verify `type` is set to `"krisp"`, not `"none"` |
| Some noise gets through                | Increase `noiseSuppressionLevel` to 85–90       |
| Extreme noise environments             | Level 100 + consider if call quality is viable  |

### Voice sounds distorted

| Symptom                      | Fix                                                |
| ---------------------------- | -------------------------------------------------- |
| Voice sounds robotic or thin | Lower `noiseSuppressionLevel` to 60–70             |
| Words getting cut off        | Reduce level; aggressive filtering can clip speech |

***

## Next steps

<CardGroup cols={2}>
  <Card title="Ambient Noise" icon="volume-high" href="/docs/advanced-features/ambient-noise">
    Add background sounds (outgoing)
  </Card>

  <Card title="Voice & Speech" icon="microphone" href="/docs/create/voice-and-speech">
    Configure STT and TTS
  </Card>

  <Card title="Language Switching" icon="language" href="/docs/advanced-features/language-switching">
    Support multiple languages
  </Card>

  <Card title="Call Inspector" icon="magnifying-glass" href="/docs/test/call-inspector">
    Debug call audio issues
  </Card>
</CardGroup>