# Spec: Multi-Device Equalizer

## New Capability: audio-device-detection

### Purpose

Platform channel bridge that enumerates current audio output devices and streams change events to Dart. Enables the rest of the system to react to device connect/disconnect without polling.

### Requirements

#### Requirement: Device enumeration on demand

The system MUST expose a synchronous query that returns the list of currently connected audio output devices as a typed list of device IDs.

##### Scenario: enumerate at startup — Android

- GIVEN the feature toggle is enabled
- WHEN `ServicioDispositivoAudio.dispositivosActuales()` is called on Android
- THEN it MUST return a list where each entry has a stable `deviceId` string
- AND built-in speaker MUST appear as `"builtin_speaker"`
- AND BT A2DP devices MUST appear as `"bt_a2dp:<MAC>"`
- AND USB audio MUST appear as `"usb_headset:<address>"`
- AND wired headset MUST appear as `"wired_headset"`

##### Scenario: enumerate at startup — iOS

- GIVEN the feature toggle is enabled
- WHEN `ServicioDispositivoAudio.dispositivosActuales()` is called on iOS
- THEN it MUST return at least the active route output
- AND the `deviceId` MUST be stable within the session using `portType+uid`
- AND calling it again before a route change MUST return the same IDs

##### Scenario: enumerate when toggle is disabled

- GIVEN the feature toggle is disabled
- WHEN any method of `ServicioDispositivoAudio` is called
- THEN it MUST return an empty list and an empty stream without errors

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(See Engram observation #2186 for complete spec with all 27 requirement scenarios)