Although Rob speaks in a highly technical manner when describing all the changes he made and why, I really recommend if you are interested in acquiring an M2 to listen to the podcast, it answers a lot of questions about the new design goals.
There are two Mojos that have been released, the original and the new 2. From my recollection, the OG was tuned as it was because the designated market in Chord’s view was for phones which due to their circuitry are noisy (RFI) devices which add brightness to the sound, and the thought was a warmer version would mate better with the intended use. Because the M2 now has lossless EQ, Rob wanted to improve the overall performance and clarity by designing it to be neutral.
@Rob Watts It would be useful to know what EQ settings give the best match to Mojo 1 based on spectral measurements of the output signal.