You have two options: One is the on-head equalization of the headphones for a completely flat response in the ear and the use of the Full HRTF Aural ID (provided). The other one is the standard high quality diffuse field equalization, and the use of the DTF version of the Aural ID (provided). The second one is fully personalized, but not as accurate as the use of the Full HRTF. You will experience some sound coloration and direction uncertainties. The reason for this is that the diffuse field equalization models the CTF in the HRTF, but it is an average over several persons and not your personal CTF. Headphones manufacturers also have their own wide band sound color emphasis. The bass level, for example, varies greatly between different headphones models and brands.