Issue with External FX

Hi all,

I’m using Cubase 10 on a Mac with an A&H QU16 mixing desk as my audio interface. I’m just trying to set up a couple of outboard FX processors so I can layer reverbs and effects.

I’ve followed the guide here:

Everything seemed to go ok, but:

  1. When I try to measure “Loop Delay for Delay Compensation” the reading comes back as 0.00, which I imagine must be wrong.
  2. When I look at the FX channels on the mix console, there is no signal although they are selected as sends for a few tracks.

I’m quite sure I am presenting the correct input/output bus signals to Cubase and have checked that on the QU-16.

Anyone have an experience setting up the same or similar who might be able to point out where I am going wrong?


To create a external efx loop from Cubase, your mixer needs to have a digital return path. So, you would record your track, connect an external efx (to a digital send - translated to analog at the mixer - from Cubase) and then patch the return of this efx into your mixer (to a new channel typically) and record the results. You have a nice mixer there but it is not really a DAW interface. It connects to a computer for live recording as far as I can tell.

When you see a DAW interface that has ins/outs (4/4, 8/8,16/16) then you are getting into an interface that will let you do what you are trying to do.

Hi mr.roos,

Thanks for your response. I think I have got a stereo digital return path via USB, so I can hear the output of Cubase via a stereo return channel on the QU-16. I think the USB connector handles the signal flow both ways.

The FX work fine on stuff that is routed directly into the desk from conventional “hardware” instruments, but not on stuff that comes from Cubase. I have configured a stereo in/out for each of the two effects that I am using (Audio Connections > External FX), and have routed those channels to the USB that connects to Cubase.

But, if the QU16 is never goign to be able to do what I want it to, would that mean I have to use something like a UR824?

The last question: Yes. Something with USB C as a minimum (that is backwards compatible with USB B, or Thunderbolt, the new ultra connection. But you need a good computer to run with Thunderbolt.

Unfortunately, the mixer you bought is basically a very nice LIVE mixer board with a USB recording option via a one way stereo out connection. Probably meant to be used use with a laptop. I read about it and it seems to be without independent isolated outs from the DAW. Remember, in the Output section of your Audio Connections pulldown window, all the outputs are listed once your ASIO driver (I will assume it has an ASIO driver but I don’t know) is connected. If you just have one stereo pair then I think that this pair gets connected to the audio Playback of the DAW for monitoring, not to split off and run to an Ext EFX at the same time. Maybe call a tech guy at Sweetwater, they can be helpful. Or even A & H.

Hi mr.roos,

Thanks for your post. I have a UR824, which I bought with Cubase Ultimate, so I will see if there is a way to make the desk work with that.

I do like being able to hear the whole mix through the desk thoough and be able to adjust everything in real time.

In terms of outputs it appearts I have 3 as per the first screenthot attached.

When I add an external device I get a warning

So it looks like the outputs get used for the external FX

There is another picture of what the audio outputs looks like after this I’ll add in a follow up post.

But yeah I will reach out to tech support to see if what I am trying to achieve is possible, otherwise go the UR824 route as you have suggested.

Audio outputs after the external device is added:

Many thanks.

OK. First off, use your Control Room as your Stereo Output source. Here I would assign 21 and 22. Make sure that you DO NOT have these OUTPUTS
(21 and 22) enabled anywhere but in the CR. The CR is something that at first glance seem unnecessary – but you need to use it even if you think you don’t. Make an effort, there’s a pay day, trust me.

OK, so looking at your other outputs…it seems as if you have 17 and 18, and then 19 and 20. If you insist on using a stereo bus, keyboards or Master Bus, I will assume, then route/select 17 and 18 as output channels. And here’s the thing. To do this operation, you need to assign those outputs to the EFX send bus on either channel on your A & H mixer. In other words, send DIGITAL audio back to your mixer from the DAW, and then you will need to exit these channels from your mixer FROM these channels EFX or AUX bus outs and physically route/cable them into two different channels on your mixer. This may seem odd at first but this process creates an analog output signal - and your EXT EFX needs an analog signal. Right?

OK, so now that you have an analog signal (X2) output, plug them into your EXT EFX, L and R. Then take the output of the EFX unit and connect these two outputs to any INPUT channels on your mixer. Assign/select these inputs to your EXT EFX (Input) bus in the Cubase EXT EFX window. Do your Latency test now and you should see that it is no longer ‘0’.

?? I hope this makes sense to you. The basic thing to remember is that to use an ANALOG EXT EFX you need to take the Digital output of your DAW and convert it to Analog, and then return this Analog signal back to the mixer where it is converted to into Digital again.