This may be controversial to some of you, but I've never used EQ on any headphone or IEM. To me, using EQ is a band-aid. If you need to EQ to get the sound you want, then you should get something that has that sound out of the box.
I found two headphone/cable combos that work with my two sources, WM-1Z with Mr Walkman firmware and TA-ZH1ES. On the WM-1Z I mainly use my LCD-X with the DHC Complement C balanced cable. This combo has plenty of natural sub bass to go with a wide smooth soundstage with excellent details. Before the Complement C, I used a AXIOS Cu. So switching to a cable with full 18.8awg of pure OCC copper litz for all four signal wires versus a cable that had 16 cores of 24awg copper that drops to 8 cores at the headphone end made a huge difference and improved the bass. But if I want a warmer sound with more bass then I'll use my MD-Z1R with a DHC Prion4 balanced cable.
So between the two headphone cable combos I have two different sounds that can fit whatever my mood is (AKA music).