@jtgofish
ASR love to quote Floyd Toole and research done at Harman.Which is fine but the findings there have also shown that the average listener does not prefer a flat frequency response .Far from it.And different types of listeners prefer different frequency response curves and these are only averages anyway so do not properly reveal the extent of this variation.
Above tells me you either have not read Dr. Toole's research or understood it.
He absolutely does NOT advocate flat-in-room response. The response should be sloping down. Otherwise the sound will seem bright.
What he advocates correctly and what is followed by many top designers in the world is flat-on-axis response, and off-axis that is smooth and similar to it, but pointing down.
On-axis response is NOT an average by the way. It is a single anechoic measurement. Of axis is made up of key strong reflections in a room. Research shows that they are most critical when it comes to off-axis performance.
Your statement about different people wanting different sound is incorrect. This has been researched across hundreds of listeners of all types. Most of us like very similar sound and in controlled testing, pick the same speaker as the best. See:
And no, we don't accept everything Dr. Toole and his research team say. I for example don't publish preference scores for either speakers or headphones.
These are the topics we discuss day in and day out in ASR. So if this is of interest for you, ASR is the right place. If you want to stick to folklore of "we are hear differently," then not so much.