I have plots that show the difference with a DSP. It's not simply
feel
good. It may be a secondary and therefore not technically preferred
but
it works well and is affordable. Again - for a single listening
position.

What sort of plots? If it's a spectral analysis, it's meaningless for
the issue I've raised of time domain problems. A waterfall plot will
show you why your solution is misguided.
I agree with the assertion that using an equalizer is affordable. In
this case you can have cheap or you can have good. You don't get both.

Scott Fraser