Hi, you are probably trying to make the VO go through the controller's external outputs. In controllers, the headphone output is most often programmed as channels 3 and 4. Unfortunately, you can not redirect the screen reader to channels 3 and 4, any audio card. Therefore, you must connect headphones directly to the computer, and then select the computer's audio card in the audio settings for headphones. Also change the screen reader output to the audio card built into the computer. Only select the master as the output of the numark controller. Then speech and eavesdropping should go to the headphones connected in the computer, and the main music output for the audience (master) should be routed through the numark controller, or any other audio card.
If on macOS it is possible to redirect the VO to channels 3 and 4 of the audio card then there is a chance that you can have a screen reader on the headphone output of the numark controller. However, I doubt this is possible, and you'll have to use the method described above, which is headphones and screen reader audio routed to channels 1 and 2 of a different audio card than the music master greeter.