Need separate loopback Signal source output channel selection

[Chuck Zwicky]

V5.20 beta 4

If I run REW on my laptop using a UA Apollo duo interface, I can route the sweep signals and signal generator to outputs 3 & 4 simultaneously, and patch channel 4 into input 2 for the loopback signal.

However, when I use my studio computer, which has over 96 channels of I/O, I can only access individual outputs, and even when linking the channels in the interface software they do not appear as pairs.

This means I cannot send the sweep signal to both of the outputs required for making measurements.


It would be very nice if the loopback signal source was also selectable individually.

At the moment there is a drop-down menu for a "timing reference output", but this does not send the signal generator to that output .

 

[John Mulcahy]

The output selected as timing reference is the one used for the loopback signal output.

 

[Chuck Zwicky]

Interesting, it does not output any signal when using the MOTU or Universal Audio Converters...

 

[John Mulcahy]

Have you selected the timing reference setting as loopback? I assume you are using ASIO, If you just want to send the signal to a second channel then check the box just below the main output on the Measure dialog and select the second output there.

 

[Chuck Zwicky]

Thanks for the reply John..!


I should have specified that I am in OSX 10.13.6

Ok I can see what I did wrong, I had not selected "use loopback as a timing reference" in the drop down menu in the measurement dialog window.
This was not completely obvious as I was setting up the measurements since this parameter only appears in the measurement dialog window., do you think it should also be in the preferences window?

I don't know why it defaulted to "no timing reference" though.

 

[Chuck Zwicky]

Also, do you have any idea why when I switch from the MOTU PCIe-424 interface to the Universal Audio Apollo interface the Apollo does not appear in the drop down menu?

 

[Chuck Zwicky]

Or why REW can see all 12 outputs of the PCIe-424 but only 8 inputs?

 

[John Mulcahy]

The output and input names depend on the how the device manufacturer has defined them, they may not (often don't) reflect the name of the device. What appears in the channel selections depends on how the device is configured in Audio Midi setup. REW offers up to 8 output channels if the device configuration supports that, which ones they map to on the device is controlled by the "Set output channel mapping" button.