Who said “ flat freq response “ is the best?

Of course without a flat response any attempt at neutrality has gone out of the window. So it makes sense that all loudspeakers/ headphones should aim to have a flat response as possible as long it's not at the expense of dynamics.

Some like me, felt that too many British loudspeakers in the past with a reasonably flat response tended to sound too polite. For me that's too great a price to pay. You may feel different.

On the other hand too great a deviation from flat gives the speaker an obvious character on everything you play and you will hear this constantly.

It doesn't have to be ruler flat, the main thing is to avoid obvious spikes. Especially if you are mixing/ broadcasting/ or in any other pro use. Pro's do tend to stick with what they know.

For the rest of us some form of tone controls / equalizer is always desirable to compensate for different rooms or recordings ect.

As usual with loudspeakers, nothing is close to perfect. The best you can do, as ever in audio, is to pick your own set of compromises.

With multiple drivers the crossover from the tweeter to the mid/bass is critical. Often its hardly ever smooth enough. Too many issues with dispersion, plus the mid starts to struggle as all drive units tend to break up badly at their extremes.

With treble units its usually at the low end where a lot of male voices are.

@ieales I've long had a mistrust of the press and regard it mostly as entertainment value only.

It would be interesting  to hear why you think phase has been largely ignored, and what did Heyser say about it? Thanks.