Logic Pro X Will Not Record From Audio Interface

Could you post a screenshot, please?

Is input monitoring enabled for the Focusrite or in Logic itself? Chances are, you haven't armed the audio track in Logic for recording (though it should be normally armed automatically), but you can hear yourself in the headphones because input monitoring is enabled for your audio interface. This means that the signal goes directly from the input to the headphones. I'd recommend to disable hardware monitoring for the interface, and enable software monitoring in Logic: Preferences > Audio > General tab > tick "Software Monitoring". That's to check whether the signal reaches Logic (you can always disable software monitoring later, if you like).

Then click the "R" icon on the audio track to arm it for recording and the "I" icon to hear the input signal:

If you still cannot record, it means that there's an issue with the signal flow. Most commonly, wrong input has been selected or you're using a wrong mode for the signal (e.g. LINE instead of MIC or vice versa).

Darn - I completely missed that there was a DBX between the interface and the mic - a disadvantage of stepping into a thread somewhere halfway. I also wrongly assumed that SM7b was a condensor mic.

- it is listed as being a "large membrane" mic, and it also very much looks like a condensor mic to me...

So, phantom power needs to be off, especially if the signal comes from a compressor anyway (the DBX would have had to deliver that phantom power if it were needed - which it isn't). I just hope that the phantom power didn't do any damage... these days I don't expect people to use a compressor before the signal reaches Logic (as it is much better workflow to use it as an insert effect later, so one has much more control over how it affects the signal). So, yeah, what Pancenter said. So: NO phantom power, and again: input gain halfway (or less), not fully open.

Yes... and the DBX does not require Phantom power, nothing in his signal chain requires phantom power.

The OP should plug his Mic directly into the Focusrite. Set the channel gain to 3/4, the Focusrite has level meters circling the knobs.The pic below shows the two colors the meters display. Normally when no signal is present they are black. Note: to OP you're stacking two mic preamps on top of each other, not a good idea, noise could be a problem.

Is the Focusrite not listed in there? Then how come Logic does seem to see it? Never mind - it must be listed there, because if it is npt listed there, Logic wouldn't be able to see it either, and it shows up in your settings, so...

this to me looks like an issue with either the Focusrite, OR your CABLE, or your SM7b - so, first try another cable, then try another mic that you know is working (if it is a dynamic mic, don't forget to turn off phantom power first). Have you already simply tried to reboot your Mac, by the way? And did it ever work before, or have you just gotten this gear?

Which version of Logic do you use? Also, as Eriksimon says, it's worth the effort to actually switch to another physical input on the Scarlett, and see what happens. Perhaps, even try switching between LINE / INST mode as well.

Besides, does your audio interface have its own setup utility? If so, I wonder what are the settings there?

The question is... is the DBX passing audio to the Focusrite? The Focisrite knobs have a visible level in a green/red light that surrounds the gain knob. Green for acceptable input level, Red is it's too much input.

The Mic you have is a dynamic Mic, Phantom power should NEVER be used on either the DBX or the Focusrite.

Make sure Phantom power is off on both.

Bypass the DBX and plug the Mic directly into the Focusrite. Then test to see if you are getting levels.

If you have enabled Phantom power on either device there may be damage to the electronics.

Have you tried it in any other app or program capable of recording sound? How about in the Sound control panel?

Did you check the device settings in the Focusrite Control app? For example that your Source Clock is set to Internal?

Sorry, didn't see that what I initially asked for is already there. Have you also tried selecting input 1? Any other choices of inputs?

You might also try plugging its USB cable into a different USB port on the computer.

To my relief I just learned that phantom power generally does not damage dynamic mics - but (to anyone else reading this) it should still be off.

What could phantom power damage, though, Eriksimon? As I know, it could fry electronics if used with a device that does not require phantom power.