App Rules (App Sound Lock)

App Rules — also called App Sound Lock — route individual applications to specific audio devices without changing the system default. Use it when you want Spotify on your speakers while your game stays on your headset.

Each rule targets an application (and optionally a window title) and owns an ordered list of device pairs. A pair contains a playback device, a recording device, or both.

Two modes

Mode	What it does	Best for
Automatic	Applies the rule's first device pair whenever the application starts or comes to the foreground.	Hands-free routing that should always be active.
Hotkey	Does nothing automatically. Pressing the rule's hotkey applies the next device pair to the running application.	Cycling an application between several devices on demand.

The modes are exclusive. A rule is either Automatic or Hotkey, never both. See Automatic mode and Hotkey mode for the details. An Automatic rule that targets one concrete application is also registered in Windows' own app audio settings, so the route survives SoundSwitch being closed — see Windows also remembers it.

How it works

App Rules use the Windows Audio Session APIs to target specific processes. Only the matched application's audio is redirected; the system default device remains unchanged.

Rules are evaluated in two ways:

• Automatic rules are evaluated whenever a new process is detected and whenever the foreground window changes.
• Hotkey rules are applied only when you press their hotkey. The rule then looks for every running process that matches it.

A rule matches on:

Field	What it matches	Example
Process Path	The process path or name. Matched as a regular expression, with a glob fallback (*chrome*).	.*chrome\.exe.* matches any Chrome process
Window Title	The title of the application's active window. Also regex with a glob fallback.	.*YouTube.* matches any window with "YouTube" in the title

If a field is left blank, it acts as a wildcard. A rule with only a Process Path matches that process regardless of its window title.

The App Rules list

The App Rules tab lists every rule with these columns:

Column	Description
Application	The process name or path the rule matches.
Window Title	The window title pattern, or blank for any window.
Playback	The first pair's playback device.
Recording	The first pair's recording device.
Mode	Automatic or Hotkey. Hotkey rules with several pairs also show the pair count, for example Hotkey (3).
Hotkey	The rule's global shortcut, for Hotkey rules.

Hover a row to see every device pair in a tooltip.

Windows assignments

Above your own rules, the list also shows — dimmed — the applications that Windows itself has routed to a specific device through its own per-app audio settings. SoundSwitch does not control these rows; they come straight from the same per-app store Windows Settings writes to:

• Read-only. There is nothing to edit on a Windows assignment row. Change it in Windows' per-app audio settings, not in SoundSwitch.
• No duplicates. An application covered by one of your rules shows up only as that rule's row, never again in this section — even when the rule also writes an assignment.
• Your rules win. If an application managed by one of your rules is changed from Windows' side, the rule re-applies its pair the next time the application is seen. Deleting the rule is the way to stop managing that application.

Rule options

Option	Description
Enabled	Turns the rule on or off without deleting it. Disabled rules are ignored and their hotkeys are not registered.
Notify when triggered	Shows a notification when the rule routes an application. Useful while setting a rule up.
Case Sensitive	Makes the process and window patterns case-sensitive.

The process picker

The Process Path field has a ... button. It opens a process picker that lists applications with their process name, window title, current playback and recording devices, and full path. Select an application to pre-fill the pattern, or use the filter box to narrow the list.

Instead of one flat list of every process, the picker groups the entries:

Group	What it shows
Has own device	Applications that already have their own audio device assigned — through Windows' per-app device setting or one of your rules. Applications that are not currently running appear here too, dimmed and labelled with a (not running) suffix. They are still selectable, so you can create a rule for a closed application.
Using audio now	Applications that have an active audio session but no device of their own yet.
Show all processes	The full process list as before. Collapsed by default; click the header row to expand or collapse it. Typing in the filter box expands this group automatically so its matches are visible, and clearing the filter collapses it again.

The filter box searches all three groups.

Creating a rule

1. Open the App Rules tab in SoundSwitch Settings.
2. Click Add.
3. Use ... next to Process Path to pick the application, or type a pattern manually.
4. Optionally set a Window Title pattern.
5. Choose a Mode:
   • Automatic — select the playback and/or recording device the application should always use.
   • Hotkey — press the shortcut you want, then build the ordered device-pair list. See Device pairs.
6. Adjust Enabled, Case Sensitive, and Notify when triggered as needed.
7. Click Save.

The rule editor window can be resized; every panel follows the new size. It scales with Windows display scaling (125%–200%), so on a large display nothing becomes too small to read.

Managing rules

• Edit: select a rule and click Edit, or double-click it.
• Enable/disable: use the checkbox in the list. The change is saved immediately and the rule's hotkey is registered or released.
• Delete: select a rule and click Delete.

When routing is applied

• Automatic rules apply as soon as a matching process starts or becomes the foreground window.
• Hotkey rules apply only when you press the shortcut, and only to the matching application's running processes.
• Routing persists while the application is running. If the application restarts, an Automatic rule re-applies; a Hotkey rule waits for the next press.

Device changes

Rules store a device identity, not just a device name. If a device gets a new id after a driver update, SoundSwitch resolves it by its device-instance path or unique name and updates the stored identity automatically. If a device is unplugged, the affected side of a pair is skipped until the device is available again.

Resetting per-app routing

If routing gets into a confusing state, open the Troubleshooting tab and use Reset under Reset Per App Audio. This clears every process-level assignment — including the routes Windows remembered for your applications — so everything goes back to the default devices. The reset applies to all applications at once, not just the ones your rules target. Afterwards, an Automatic rule applies its device again the next time the application runs (and registers it with Windows again); Hotkey rules wait for you to press their shortcut.

App Rules vs Profiles

App Rules route individual applications to specific devices. The system default device does not change.

Profiles change the system default device when a trigger fires. This affects every application that uses the default device.

See Profiles vs App Rules for the full 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) and the trigger source. No process path or window title is sent. See Privacy and Telemetry for details.

In this section

• Automatic mode — one pair, applied whenever the application matches.
• Hotkey mode — cycle device pairs with a shortcut.
• Device pairs — build and order the playback/recording combinations.
• Examples — ready-to-adapt rules for common setups.
• Troubleshooting — when a rule or hotkey does not do what you expect.