I have a pair of these headphones:
They work fine for audio input and output on my Android phone (LG G5) and my 2015 MacBook Pro (tested with Quicktime recorder).
But when I plug them in to my 2017 MacBook Pro and record audio the sound is barely detectable, even when turned all the way up (on input and output). They are fine for audio output though.
Did Apple change something between the two MacBook Pro models? Is it more likely that my MacBook Pro has a defective connector?
Here are the audio settings on my 2017 MacBook Pro: