The Advantages of Floor Coupled Up-Firing Speakers

[el`Ol]

You would need some electronics for adding the signals again. Is your parametric sufficient for doing the mid/treble? You have to be lucky to get a good frequency response with a CFS (like I was with the HX201).

[el`Ol]

BTW,
is it a problem for you to use an additional pair of bass speakers? Heavy boosting is a torture for fullrange drivers.
Another option:
If you use the Sony you could build a passive crossover that can be really messy, the Sony will correct it.

[markus76]

Originally Posted by el`Ol

The algorithm would record two main impulses, the direct one and the ceiling reflection. If you mean by "gating" that it makes a cut after the direct impulse and corrects its frequency response, this would be wrong. The frequency response of both together would be distorted.

There are many more reflections that would be recorded. "Cutting" out all reflections and correcting only the direct sound is the right thing to do because if the direct sound is not flat there's no way for indirect sound to make it sound flat again.
Nevertheless, if the direct sound is flat and the indirect sound is not, coloration will be perceived. So the goal is to make both the direct and indirect sound flat. That's something constant directivity loudspeakers provide.

[markus76]

Originally Posted by graaf

Dspeaker Anti-mode ... is it strictly a subwoofer device ...?

Yes.

[markus76]

Originally Posted by el`Ol

If you use the Sony you could build a passive crossover that can be really messy, the Sony will correct it.

What "Sony" are you talking about?

[el`Ol]

I mean the TA-FA1200ES, a digital amplifier with room correction.
TA-FA1200ES (TAFA1200ES) : HiFi und Home Audio : Sony
It just ran out of production, no more information available at the US site.
As far as I know Panasonic also cancelled their digital amps, this full digital thing seems to be dead.

[el`Ol]

Originally Posted by markus76

if the direct sound is not flat there's no way for indirect sound to make it sound flat again.

From my experience with the HX201 CFS I would say the opposite.

Originally Posted by markus76

Nevertheless, if the direct sound is flat and the indirect sound is not, coloration will be perceived.

Sounds like a contradiction to me. An indirect sound with not-flat FR can colour the perceived result, but not correct it?

[el`Ol]

Originally Posted by markus76

So the goal is to make both the direct and indirect sound flat. That's something constant directivity loudspeakers provide.

You neglect what walls do. They don't absorb all frequencies to the same degree. What you can achieve is an equal frequency response of all reflections. To go back to the weaker term "controlled directivity": You can achieve this when you get the constand directivity characteristics down to the frequency where you can do real deconvolution (Olive estimates 500 Hz). But then all reflections are lacking the frequencies below.

[markus76]

Originally Posted by el`Ol

You neglect what walls do.

What do "normal" walls do? Nothing if they are rigid. They just reflect. Drywall (typically used in the US) absorb lower frequencies which is desirable.

[markus76]

Originally Posted by el`Ol

From my experience with the HX201 CFS I would say the opposite.

Sounds like a contradiction to me. An indirect sound with not-flat FR can colour the perceived result, but not correct it?

A very good summary about what psychoacoustics knows can be found in Wittek's PhD thesis: http://hauptmikrofon.de/HW/Wittek_thesis_201207.pdf