Topic: Output on Fireface from a different USB input?

Hi there,

I have a Fireface UCXII and my studio monitors are connected to that. I have just got a guitar processor which has it's own USB audio interface.

I would like to send audio from the guitar processor into my computer (Mac) and then output through the studio monitors via USB. To put it a different way, plug the USB output of the guitar processor into my computer and then have the audio come out of the studio monitors that are connected to the fireface.

Can this be done?

I know that I could just take 2 analog outs from the guitar processor and into the analog inputs on the fireface, but I'm looking for a way of avoiding too many cables on my desk!

Re: Output on Fireface from a different USB input?

You could create an Aggregate Device with the two audio interfaces. Google it, there are many tutorials on the web.

Regards
Daniel Fuchs
RME

Re: Output on Fireface from a different USB input?

Hi, thanks for the reply.

I have created an aggregate device, but now I'm not sure what to do with it.

How do I route the audio from the guitar processor USB in to the Fireface analog out? The inputs do not appear in TotalMix (understandably).

I did manage to set something up with a Mac app called LoopBack, but there was very noticeable latency.

4 (edited by ramses 2022-06-22 15:11:44)

Re: Output on Fireface from a different USB input?

I think the best solution is to connect the guitar processor directly to the UCX II.
You avoid any latency over USB and through this loopback tool.
It will also make the signal flow easier and more straight forward.
Also monitoring will benefit from much lower latencies, if audio needs only to be routed on the UCX II itself.
Then you have no round trip latencies over USB etc ...

BR Ramses
UFX+, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1650v4, Win10Pro21H2, Cub12Pro

Re: Output on Fireface from a different USB input?

You are absolutely right.

I'm just trying to find a clever way to avoid the spaghetti of cables on my desk!

6 (edited by ramses 2022-06-22 15:34:23)

Re: Output on Fireface from a different USB input?

Playing air guitar ? wink Sorry couldn't resist.

I think it's quite logic that there is no other solution than that.

Because the RTL over USB is always much higher compared to converter latency and forwarding audio locally on UCX II from input to output port. Additionally latency over USB can become quite high depening on the buffer you configure.
And here you have USB two times (PC <-> UCX II and PC <-> Guitar Processor).
Then you have additionally a little latency by the processing of loopback application and finally you will have to route the different audio flows in the DAW for monitoring.

So you have always this flow for monitoring

                DAW
                   |
       Aggregate Device /
+---- Loopback Application ----+
|                                              |
|                                              |
USB (around 4ms)             USB (around 4ms)   latencies over USB depend on configured buffers (*)
|                                              |
|                                              |
UCX II                              Guitar Processor
|
| D/A conversion
|
Monitoring

(*) I only want to demonstrate, that you are here most likely already in the range of around 10ms

Better:
            DAW
               |
              PC
                |
             USB
                |
      Fireface UCX II   (audio flow for monitoring local on the UCX II)
      |                  |
    A/D             D/A
      |                  |
Guitar            Monitors
Processor

Time for AD + DA conversion at 44.1 kHz: around 0,11 + 0,13 = 0,23ms (plus maybe a few samples through the digital matrix on the UCX II).

And now pls tell me how to avoid all this latency if not connecting the guitar processor directly to the UCX II?!
I think there is no other solution than that.

BR Ramses
UFX+, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1650v4, Win10Pro21H2, Cub12Pro

Re: Output on Fireface from a different USB input?

Thank you for all of your help.

It looks like I'm going to have to reconfigure my desk!

Re: Output on Fireface from a different USB input?

1-2 cables are not that expensive, try it out and look what the difference is. Then you know.

BR Ramses
UFX+, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1650v4, Win10Pro21H2, Cub12Pro