not sure Miracle has the mid for me.
It sounds a bit recessive on mid and the highs are bit rolled off.
I like the highs in Miracle, but so much for the mid.
The bass is just at the right amount. I have no issue with that either.
Miracle is a well tuned CIEM, but it has "color" for sure. So, I cannot call it "Neutral". For me, not emphasized on bass is not the same as flat frequency response.
Never heard of the Merlin, so there will be no comment on that.
the socket cable's sound is really really flat and not cool for me, Miracle need after market cable 100%, will make the highs change 100% and the mids come out, and the change isn't subtle with them, i had Miracle twice and tested many cables, for me its a crime to use it with the stock cable, when i went back for it and did A/B it with other HQ cables i was shocked.... the Miracle isn't 5/5 with the stock cable...