Hello, I am also completly new to Dirac and read this conversation because I was also thinking that correcting the upfiring Atmos speakers to flat by Dirac will destroy HRTF. I assume that after Flak explained that Dirac measurement will not "see" the applied dolby atmos coloration filter for upfiring speakers - we don't worry about it any more. The only problem for now is adjusting the timing? And we should do it more or less like GXAlan explained?