Applies to Clarett, Clarett USB, Clarett+, Scarlett 16i16 4th Gen, Scarlett 18i16 4th Gen, and Scarlett 18i20 3rd and 4th Gen.

For all smaller Scarlett interfaces, apart from the ones listed above, you can change the sample rate in your recording software (DAW), in Focusrite Control or, from Audio MIDI Setup.

• You can only change the sample rate for the all models of Clarett, and Scarlett 18i20 3rd Gen in Focusrite Control or Audio MIDI Setup — not your DAW.
• You can only change the sample rate for the Scarlett 16i16, 18i16, and 18i20 4th Gen in Focusrite Control 2 or Audio MIDI Setup — not your DAW.

The reason for this is, these interfaces are class compliant and use Apple’s Core Audio USB driver, which is built into the operating system. When you switch between different sample rate bands (i.e. 44.1/48Khz, 88.2/96kHz and 176.4/192kHz), the number of channels that the interface presents to the operating system changes due to its channel count. For example, 4x channels of ADAT are lost at 88.2/96kHz and more ADAT channels are disabled at 176.4/192kHz.

Our firmware tells Core Audio that the channel count has changed when this occurs. We have to do this otherwise Core Audio still thinks there are, for example, 20 outputs available when the device is set to 88.2/96kHz, at which point audio won’t play back at all.

Due to a change in Core Audio in macOS 10.13 and above, the way it changes sample rate correctly between bands is now slightly different to before. We’ve had to make a change to Focusrite Control to facilitate this and whilst some DAW manufacturers have also added the change, many have not. This is the reason the sample rate cannot be changed from within most DAWs.