Please disregard this post and see the latest final A4000 measurements (frequency response graphs) and comparisons with Etymotic ER2XR using v1.0 of my IEM Measurement Rig.
These measurements are made on my DIY IEM measurement rig and are not accurate, and don’t necessarily represent what you might hear, especially before 60 Hz (huge sub-base roll-off) and after 10 kHz (and maybe even after 3 kHz as my ER2XR graph is very different compared to Crinacle’s post that). You can use it just to get a comparative idea, hence the comparison with ER2XR to give you a point of reference. Improving the rig is an ongoing process.
Here is Crinacle’s ER2XR graph for reference
It looks like final went with the mids to bass rise like in the E series and the highs of the A8000 on A4000.