Using Focusrite interface to stream more than 2 L/R inputs without glitches


New Member
I have a Clarett+ 4pre USB, using for recording and streaming on OBS on Mac. I mainly stream live music, sometimes I need to setup more than L/R pair of microphones and mix it in a DAW before to stream.

It known that OBS just sees the input 1 and 2 for streaming. If you want to capture the computer sound, or to mix other inputs of your interface to the stream, it is not possible without a 3rd party software. Focusrite website recommend to use the iShow Audio Capture as a virtual cable, in order to make OBS to see the output as the input 1&2 of the aggregate device.

I tried this approach, and I've tried many other apps for the virtual cable, such as BlackHole and Soundflower. It worked for a while, but none of them worked more than 10 minutes of continuous streaming; after a random while, the audio become noisy, glitching every second, and I need to restart the audio engine while streaming to fix the glitches. I've found many people with the same issue in this forum and also in other forums.

I solved the issue using a different software with a different approach: Rogue Amoeba Loopback (, that doesn't requires to create an aggregate device. It worked like charm, easy to use, and no audio quality issue at all.

I really recommend using Loopback instead of iShow.

Adding to that, on the devices that offers a loopback feature, such as Scarlett 18i20, would be nice if Focusrite implement a function where the loopback could be mapped as input 1&2, it would be no need of 3rd party software at all.

I hope all of this could be helpful, because I was searching for this solution for a long time, and many other people must have the same issue.