inverse response speaker flattening

[Martin Czech]

There is one thing I wonder about:

You have music from digital sources all the way, till power amplifier. It
would be no problem to ship a little digital in/out box with a measuring
microphone, so that anyone can measure the frequency response of his room
and his speakers, the box takes the inverse to filter the CD data. That
should give an almost ideal response for that single measuring point in
space and hopefully around it.

Of course, once the speakers are flattened, any personal taste could be
applied as well (bath tub).

One problem could be that shitty bass chassis could not take the needed
power...

I have never seen any advertisement for such an apparatus, it seems that
something like that simply does not exist.

Another question:

In the 70ties people thought about switching amplifiers.
I.e. DAC amplifiers. The audio chain would be digital up to
the speakers. Are there any reasonable advances/designs
today?

m.c.