When I first started out recording myself on cello, I would end up having to find creative ways to increase the volume of my recordings without noticeably distorting the sound. I had two different types of microphones that I wanted to use simultaneously which eventually led me down the path of creating an aggregate after a friend sent me this article https://support.apple.com/en-us/HT202000 that discusses combining multiple audio interfaces through the use of an aggregate device. This article got me going in the right direction, but I had to do a lot of experimenting to find the custom solution for my specific set up which consisted of:
(1) an iMac computer with Logic Pro X
(2) the Apogee USB MiC
(3) a CAD C9 mini condenser mic that hooks up to my Behringer X1204USB audio interface
Below are the steps that worked for me:
Step 1: Create the aggregate device using the three ‘Audio Devices’ that pertain to my setup. For the purposes of this example, the aggregate device that I created is called ‘My Aggregate’. Navigate to Finder > Go > Utilities > Audio MIDI Setup. Click on the ‘plus’ button in the bottom left hand corner of the ‘Audio Devices’ window and select the ‘Create Aggregate Device’ option. You can double click on the defaulted aggregate name to type in the name of your choice. The Apple support article mentioned above goes into more detailed steps on creating the aggregate and is worth a read. In my case, I selected the USB Audio CODEC device that had the 2 Ins, the USB Audio CODEC device that had the 2 outs, and the MiC device that had the 1 In.
Step 2: Open up a Logic Pro project and go to the global settings on the ‘Devices’ tab to select ‘My Aggregate’ as the audio ‘Input Device’ and ‘Output Device’. To get to the global settings: Navigate to Logic Pro X > Preferences > Audio > Devices
Step 3: Create at least 2 audio regions in your project and double check that the ‘Input device’ and ‘Output device’ settings point to ‘My Aggregate’ before clicking on the ‘Create’ button.
Step 4: The ‘Input’ setting on each of the 2 channel strips will have to be changed to reflect the ‘Input Channels’ settings in the aggregate device settings window. In my case, since I selected my Behringer audio interface first when I created the aggregate, the first 2 input channels are being utilized by that audio device. I selected the MiC second when creating the aggregate, so input channel 3 was assigned to that audio device. In my Logic project, I need to make sure that one of the audio regions has ‘Input 3’ selected on the channel strip while the other audio region can remain at the defaulted value of ‘Input 1’ on its channel strip.