@ptss wrote: "responses to this thread have virtually all been to say why frequency response is unimportant. "
Imo frequency response is the most important thing, but imo "frequency response" MUST include the off-axis behavior of the speaker because most of the sound that you hear in a non-anechoic, non-nearfield setup starts out as off-axis sound. One place where you and I disagree is on WHAT that frequency response should look like.
"No one has responded with any indication they know why it’s not practicable to make speakers with “flat” frequency response."
It can be done but imo it's an uninformed mis-allocation of funds and effort for home audio. In my opinion (and in the opinions of Floyd Toole, Sean Olive, Earl Geddes, and most other speaker designers) "flat" is not the goal because it doesn't sound as good as a gently downward-sloping curve.
If you want "flat", you might want to thoroughly check out Neumann studio monitors. I did back when they were Klein & Hummel, and elected not to become a dealer. But they are a wonderful tool for recording studios.
Duke