Logic Pro 9 selecting input in Logic Express


New Member
Mac OS 10.6.5
Logic Express 9.1.3

I have two Edirol AU-1X usb audio interface plugged into my Mac. It shows up in the hardware profile as two different pieces of hardware, but in logic it only shows the one UA-1X. I have gone to my environment window to try to assign it manually but it only shows one device.
I have different audio playing on either unit. No matter my input selection I hear the piano music. If I unplug that unit I can hear the singing group which I have coming through the other UA-1X. If I plug the other one back in I hear piano music again.
Why can I see the two different units in the system hardware, but cannot see them as two in logic. Can someone give me some direction.


Staff member
Hi there, welcome to the LUG. This issue has to be solved outside of Logic. Open the Audio Midi Setup Utility a.k.a AMS, to be found in the Applications -> Utilities folder. Here you need to set up what is known as an aggregate Audio Device, in which Mac OS combines two or more Audio Interfaces into one aggregate unit. Setting it up is pretty much self explanatory. This will then appear in Logic as one device, but with all the Input and Output Channels of both combined.

kind regards

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