How to reamp dry signal from quad cortex when a different interface is used for output?

Quad Cortex
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1

So I have an interesting setup here with my macbook pro and logic pro.

I have two interfaces connected:

  • Focusrite Scarlet 2i2
  • Quad Cortex

The Focusrite Scarlet 2i2 (connected to macbook via USB C) is where I have my XLR condenser microphone (connected to the back XLR input 1) and my left+right KRK Rokit 5 studio monitors.

The quad cortex (connected to macbook via USB A-B 2.0 + power adapter) is where I have my 1/4” jack from input 1 to my guitar.

In logic pro, I have my audio settings tab setup so that the QC is my input device, and the focusrite scarlett 2i2 is my output device.

Usually, I can simply record a wet signal by creating an audio track, where input=stereo input 3+4 and output is default (so to my scarlett 2i2 which has the studio monitors connected)

I can also record a dry signal by creating an audio track, where input=stereo input 1+2 and output is default (again to studio monitors).

What do I do if I want to reamp the dry signal though? Sure I can slap some NDSP plugins that I also have loaded onto my computer. But… what if I wanted to play around with the amps and cab sims and pedals that are on my QC to color my dry signal?

And how do I listen to that colored dry signal? Is my setup making this possible? All the forum posts so far I see I think assume that the QC is your sole and only interface– which also implies that the monitors are connected to the QC.

For alternative reasons, I want to keep my Scarlet 2i2 for my studio monitors and microphone.

2

have you looked at creating an ‘aggregate device’ on the Mac Audio/midi settings?

This allows you to use multiple devices simultaneously. Can get a little confusing with monitoring, but we can walk you thru it here.

3

Ok, based on playing around my inputs and outputs, here is what I have learned so far.

At the most barebones level, suppose you have your macbook, quad cortex connected to macbook, logic pro and an instrument connected to input 1 in the QC (a guitar for example).

When the guitar produces signal (strum, pick etc.), there will always be a dry signal outputted to USB OUT 1/2. I don’t think this is ever changeable. In fact, the quad cortex I/O settings menu will tell you this if you tap the info icon on OUT 1/2 after tapping the USB icon.

The rest of the USB OUTX/Y are manual outputs.

By default for many presets, the final output is to Multi-Out. I don’t think the meaning of multi-out can be changed, but this will always be outputting to:

  • XLR outs 1/2
  • TLR outs 3/4 (most often, if people use QC as their sole and only monitors, their studio monitors connect here)
  • USB out 3/4

So in logic pro, if you want to hear your “wet” signal, you set your track to input QC USB out 3/4. The track output can go to default, which is usually your configured master output (in my case, scarlett 2i2).

Okay now suppose you have a track for your dry signal that you want to reamp. First, you would record your dry signal by creating a new track to input 1/2, then output to default (for now…)

Once you have the dry signal, suppose you want to color it. The trick is to make logic pro send the dry signal back to the quad cortex. This is what I cannot figure out, but other forums have suggested that I can can change the output to something in the QC??

Now, in order to do all of this though, you need to actually setup an aggregate device on your OS (macOS makes this easy)

4

Here is a screenshot of my inputs and outputs btw:

Screenshot 2025-11-26 at 4.59.17 PM
Screenshot 2025-11-26 at 4.59.17 PM969×584 60.6 KB

5

Ok, I figured it out! It was pretty tricky, but it’s spelled out in the manual here: https://downloads.neuraldsp.com/file/quad-cortex/Quad%20Cortex%20User%20Manual%202.3.0.pdf

Specifically page 89 and 90. The tricky part is that based on my aggregated setup, the mono dry signal isn’t coming from “input 1” in logic. It’s QC input 1, which according to the picture above would be “input 5” in logic.

Following that translation from the IO listed in the photo above to what logic has, this is possible now!