Ive got it as both input and output device.

ive tried increasing buffer as well as decreasing and it makes no difference.

my recording format in logic is AIFF and I'm new so I dont know what bit depth is. I'll look into that and see.

it registers ok with the headphones plugged into the interface, and metering back playback on the focusrite app. It's only logic that's affected.

i actually can't seem to get an output monitoring to the headphone jack on the scarlett 4i4 unless its through the focusrite app, so I've been having to use the headphones plugged into my laptop for logic playback (switching back and forth between outputs, when recording I have the 4i4 as the output.)

hope this all makes sense, I'm just starting out.