The mic was fine. Input 1 had been rerouted to a virtual channel.
A client got in touch about his Universal Audio Apollo Solo. It had been working earlier in the week. Now nothing from his mic or line inputs was getting into Logic Pro. He hadn’t changed anything, and he’d spent the last two days trying everything he could think of.
What I checked
We connected on AnyDesk and WhatsApp so I could see his screen. The basics were all fine. The Apollo showed up in Logic and in the Mac’s Audio MIDI Setup. His track was set to input 1, and his mic was plugged into input 1 on the back of the Solo. As far as Logic was concerned, everything was connected correctly.
What was actually wrong
Then I checked Logic’s I/O assignments and labels.
Input 1 wasn’t coming from Mic/Line 1. It was coming from Virtual 2.

That routing lives one layer down, in UA’s Console software. In Console’s settings, on the I/O Matrix, input 2 was set to Mic/Line 2 as normal. Input 1 was set to Virtual 2. I’ve seen the I/O Matrix stop the signal reaching Logic another way too, on an Apollo Twin where the I/O Matrix had been left blank while the client was troubleshooting.

Quick bit of background. The I/O Matrix decides what feeds each of the inputs your recording software sees, and you can’t change it from inside Logic. So Logic was listening to input 1, and input 1 wasn’t coming from the mic socket at all. He hadn’t touched it. He’d never needed to open Console before.
The fix
One setting: input 1 back to Mic/Line 1. The signal was straight back in Logic. We did a couple of test recordings, then I used the rest of the time to check the rest of his setup: some gain staging, and making sure his monitoring worked and he could control his headphone and speaker volume from the Solo’s front panel.
Why did it change?
I honestly don’t know. He mentioned some power problems in his studio, and that his Mac had sometimes shut down without being turned off properly. That could be it, but I’d expect a power problem to reset everything to factory settings, not change one setting. I can’t say for sure.
He left with his mic working, knowing how to fix it if it happens again, and with the rest of his system checked over.
If your Apollo shows up in your DAW but there’s no signal, check Console’s I/O Matrix before anything else.
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