---
url: 'https://soundswitch.aaflalo.me/usage/app-rules.md'
description: >-
  Route individual applications to specific audio devices in Windows without
  changing the system default — keep games on headphones while music plays
  through speakers.
---
# App Sound Lock (App Rules)

App Sound Lock lets you route **individual applications** to specific audio devices — without changing the system default. This is the tool you reach for when you want Spotify to play through your speakers while your game audio goes to your headphones.

## How It Works

Behind the scenes, App Sound Lock uses Windows Audio Session APIs to target specific processes and route their audio stream to the device you choose. The **system default device remains unchanged** — only the matched application's output (or input) is redirected.

### The Matching Engine

Each rule is displayed in a list with the following columns:

| Column | Description |
|--------|-------------|
| **Application** | The process name or path that the rule matches. |
| **Window Title** | The window title pattern to match (can be blank to match any window). |
| **Playback** | The audio output device to route the application's sound to. |
| **Recording** | The audio input device to route the application's microphone access to. |

### Rule Fields

When adding or editing a rule, you configure these fields:

| Field | What It Matches | Example |
|-------|-----------------|---------|
| **Process Path** | The full process path or name — matched as a **regular expression** (or a glob pattern fallback like `*chrome*`) | `.*chrome\.exe.*` matches any Chrome process |
| **Window Title** | The title of the application's active window — matched as a **regular expression** (or a glob pattern fallback like `*YouTube*`) | `.*YouTube.*` matches any window with "YouTube" in the title |
| **Playback** | The audio output device to route the application's sound to | Speakers, Headphones, etc. |
| **Recording** | The audio input device to route the application's microphone access to | Microphone, Virtual Cable, etc. |

If a field is left blank, it acts as a wildcard — meaning it matches **any** value for that field. A rule with only a Process Path set will match that process regardless of its window title.

### Rule Options

| Option | Description |
|--------|-------------|
| **Enabled** | Toggle the rule on or off without deleting it. Disabled rules are ignored by the matching engine. |
| **Notify when triggered** | Show a banner notification when this rule successfully routes an application. Useful for confirming matches during setup. |
| **Case Sensitive** | When checked, the regex patterns match with case sensitivity. |

### The "..." Button and Process Picker

The **Process Path** field has a **...** button. Clicking it opens a process picker dialog that lists all running processes, showing their **Process Name**, **Window Title**, current **Playback** device, current **Recording** device, and full **Process Path**. You can select a process from this list to auto-fill the Process Path field, or use the **Filter** textbox to narrow the list.

## When Rules Are Applied

App Sound Lock monitors the system in two ways:

1. **Process Detection** — Whenever a new process starts or is detected, all enabled rules are evaluated against it.
2. **Foreground Window Changes** — Whenever you switch to a different window, rules are re-evaluated against the newly focused application.

Once a rule matches a process, the application's audio is immediately routed to the configured device(s). The routing persists as long as the process is running.

## Creating a Rule

1. Open the **App Rules** tab in SoundSwitch Settings.
2. Click **Add**.
3. The **Add Rule** dialog appears with a prompt: *"Select the process of the application whose audio you want to control."* Click the **...** button next to Process Path to open the process picker.
4. Select a running process from the picker. The **Process Path** field is auto-filled based on the selected process. You can edit it manually for more precise matching.
5. Optionally set a **Window Title** pattern.
6. Choose the target **Playback** device and/or **Recording** device from the dropdowns.
7. Adjust the **Enabled**, **Notify when triggered**, and **Case Sensitive** options as desired.
8. Click **Save**.

![App Sound Lock Rules List](/images/AppRules.png)

![Add App Sound Lock Rule](/images/AppRules%20Add.png)

## Editing and Managing Rules

* **Edit**: Select a rule and click **Edit**, or double-click the rule in the list.
* **Toggle**: There is no checkbox to quickly toggle rules on or off in the list; use **Edit** to change the **Enabled** option.
* **Delete**: Select a rule and click **Delete**.

## Practical Examples

| Use Case | Process Path | Window Title | Playback Device |
|----------|-------------|--------------|-----------------|
| Route all Chrome audio to speakers | `.*chrome\.exe.*` | *(blank)* | Speakers |
| Route YouTube (in Chrome) to headphones | `.*chrome\.exe.*` | `.*YouTube.*` | Headphones |
| Route Discord voice chat to a specific mic | `.*discord\.exe.*` | *(blank)* | Recording: "Blue Yeti" |
| Route a specific game executable | `.*eldenring\.exe.*` | *(blank)* | Gaming Headset |

## Resetting Per-App Routing

If audio routing gets into a confusing state, the **Troubleshooting** tab includes a **Reset** button under **Reset Per App Audio**. This clears all process-level device assignments and allows Windows to reassign applications to their default devices, after which App Sound Lock rules will reapply on the next process or window event.

## App Sound Lock vs Profiles

> **App Sound Lock** routes **individual apps** to specific devices. The system default device does not change.
>
> **Profiles** change the **system default device** when a trigger condition is met. This affects all applications that use the default device.
>
> See [Profiles vs App Rules](../usage/#profiles-vs-app-rules) for a detailed comparison.

## Telemetry and Privacy

When telemetry is enabled, App Rule activations are counted anonymously. SoundSwitch records only a SHA256 hash of the matched process basename (the first 8 hex characters) — no process path or window title is ever sent. See the [Privacy and Telemetry](/legal/telemetry.md) page for full details.