- Focusrite Control app for iOS
- Scarlett 6i6, 18i8, 18i20 (2nd Generation)
- Scarlett 4i4, 8i6, 18i8 and 18i20 (3rd Generation)
- Clarett Thunderbolt Range
- Clarett USB Range
- Clarett+ Range
- Red Range
The headphone outputs on all of the above interfaces, apart from the Red Range, are controlled using analogue potentiometers on the units, as well as the corresponding volume fader for those outputs in Focusrite Control.
To use Focusrite Control for iOS to alter your headphones' volume, it's important to also have the headphone output dial on the interface itself turned up. You can then make adjustments to the level using the fader in the iOS app.
The headphone outputs on the Red Range are digitally controlled and so can be adjusted exclusively from the iOS app.