Frequency response + or - 1 dB ??

Well, it didn't happen. When I was done, it was a truly dreadful sounding speaker.

It was probably not measured properly and not really flat. Why else would it sound dreadful?

you can but only at one point in space

@ptss 

It's a matter of preference and each recording itself has a different balance so the response of the speaker should be adjustable not fixed. But audiophiles dislike adding anything in the signal path. 

Would you please describe your current speaker syste, as well as any widely available commercial speaker you stan?

I don't have a current system. None that meet my standards can be found for a reasonable cost or perhaps even at any cost. 

The last speaker I had were called Green mountain audio chroma. However, they suffer from severe colorations which make them sound very cold. Additionally these speakers have zero baffle step compensation, in addition to poor bass response. There's no evidence they are time coherent either, only the manufacturers claim. 

@ptss 

Its interesting to me that responses to this thread have virtually all been to say why frequency response is unimportant.

No one has responded with any indication they know why it’s not practicable to make speakers with “flat” frequency response

whether its important or not is irrelevant. The reason its not possible is because it would take too many iterations and man hours to optimise the response to be flat. We therefore settle for flatness within a specified limit such as +- 3db.
And as duke suggests , flatness at one point is pointless. But then flatness at every point in space is even harder to achieve. DSP will only optimise one point in space.  Typical rectangular shaped cabinets are not the best for flat response. But spherical speakers are impractical to make so we have to accept the peaks and dips you get with a non spherical box.