Applies to: 16i16, 18i16, and 18i20 4th Gen

The Scarlett 18i20's Alt (alternate) button gives you the ability to alternate between two sets of monitor speakers. This is useful for referencing your mixes on a different set of speakers.

You need to configure the Alt function in Focusrite Control 2's routing tab, and you can be trigger it from Focusrite Control 2 or using the Alt button on the front panel of the interface.

When Speaker Switching is enabled, the main monitor mix, i.e. what is currently routed to Line Outputs 1-2, is copied to Line Outputs 3-4.

To set up speaker switching

1. Connect a second pair of powered speakers to Line Outputs 3-4 on the back of your Scarlett 16i16, 18i16, or 18i20 3rd Gen interface.
2. In Focusrite Control 2 go to the Routing tab to turn speaker switching on or off.
3. In the Routing tab, you can also select the audio source which will be sent to Monitor Outputs 1-2 and the Alt Monitors connected to Line Outputs 3-4.
   
4. You can switch between your main monitors and the Alt pair of monitors by clicking on the Main or Alt buttons on the right under the monitor level control. Or by pressing the 'Alt' button on the front of the interface.
5. The Main monitor/output dial on the interface will change the levels for the Main and Alt pair. The 2 levels are separate so that you can set the Main monitor output level to a different level from the Alt monitors. 

When speaker switching is not turned on in Focusrite Control 2 the Alt button on the front of the interface will not work and when pressed will flash when pressed. When speaker switching is on in Focusrite Control 2 the Alt button on the interface will be White for the main monitors (1-2) and Green when using the Alt monitors (3-4).