Ableton Forum

This is from their 'User Guide':

Focusrite Control’s Loopback feature lets you record other audio sources from within your computer
(e.g., the audio output from a web browser). Loopback uses the Clarett’s “virtual” inputs, which have
no physical connectors on the hardware interface itself, but may be selected in the DAW as signal
sources for recording in the same way as any other.
Thus by selecting the Loopback output as the recording source on a mono or stereo DAW track, you
can record from another software application into your DAW. Note that your computer will assign
DAW 1 and DAW 2 as the default sound output channels.
An example of configuring Loopback in Focusrite Control is given below:
1.
In the Loopback output tab, select the audio source you wish to loop back into your DAW.
Default is
Playback 1-2
.
2.
In your DAW, ensure that the Loopback tracks are enabled for recording.
3.
Create a new audio track.
4.
Important!
- MUTE THE DAW CHANNEL. If you are routing the output of the channel you are
recording back to DAW 1 & 2, a feedback loop will be created, potentially damaging for your
speakers, or worse – your ears.
5.
Check that the Loopback output is not muted.
6.
Set the DAW channel to record enable.
7.
Now, any audio playing on your computer, e.g., a separate audio replay program
or from an Internet browser, will be routed into your DAW ready for recording.
Hit record in your DAW to capture the audio.

**********************************

Does anyone know how to make this work?
In the first paragraph, what is the meaning of 'Loopback uses the Clarett’s “virtual” inputs which have
no physical connectors on the hardware interface itself, but may be selected in the DAW as signal
sources for recording in the same way as any other.'

There are no clarett virtual inputs visible in the DAW, and if there were what would they look like?
And that's just the first paragraph.

the first thing you need to do is to go into Live's audio prefs, and configure the Clarett inputs and outputs that you want to use.

once you've done that, the channels should appear in the Live input/output routing selectors for each track...

Thanks. I've decided to use soundflower by cycling74 which is free and easy to set up.
I don't know why focusrite doesn't employ some competent technical authors, because that 'user guide' is beyond me. Just as well they have some usable presets.

This is an oldish thread but it's still a top search result for this issue.

The inputs I needed to use with an 18i20 were 9/10, they don't look any different to the other inputs in Ableton.
This is in between the hardware inputs and the ADAT inputs.
For units without ADAT support it's probably the last inputs available instead.

I found it by playing some audio in another program, enabling all the inputs and looking for active meters in Ableton.

I didn't find any Loopback output in Focusrite Control on my Clarett 4PreUSB, but I just used the S/PDIF Out>In and as a physical loopback via RCA cable. Works. And as it's digital, it should be lossless I guess...

Focusrite Control is a pain and not all the intuitive in my book. However, it can be done. Save your settings and load the System Playback preset and it should work. My 4Pre Thunderbolt uses inputs 11/12.