Acoustics experts - a little help please

@cundare2 Not exactly sure but off vertical axis response drops off pretty quick. I think its probably because of the horns that are built into the front baffles of the Anteros. 

You are right and it is even more complex than just the right balance  of reflections locations/diffusion locations/absorption locations...

The acoustic material content of the room matter, his size parameters , his geometry, his topology (windows doors apertures) and his acoustic material compositioncontent...

Without being there  it is difficult to gave advices  if we are not  a  very professional experimented acoustician...

Anyway i used non esthetical resonators and it takes me 2 years to be done with them i had experience really in one small room only ...

 The only thing i know is that any room can be tuned, i tune mine with a speaker in a corner for example near the wall  and the other not in a corner ...

Every room is different. Every ear is different. Every speaker is different. Nobody can answer your question. Broad brush statement is, a mix of absorption and diffusion work best. Look for a decay time around 250 or so.

@deep_333  why would you say:

"Setting expectations straight, 3D is a foolish concept concept in purist stereo." -?

I'm primarily listening to CD thru McIntosh MX-113 and a 2200 amplifier, and Sonus Faber Cremona speakers. My experience with this is 180 degrees opposite your assertion.

It is dependent on the recording quality (and most modern releases won't cut it) but in my treated room listening to pop, jazz, classical and even some older electronic music I can get a massive sound stage with well-defined height, width & depth. Sometimes the center image seems to float behind the speakers and sometimes well on front of them. On many tracks a single element will sound like it's behind the wall that's behind my head.

The effect can be even more pronounced when listening to my (spotlessly clean) vinyl with a Rega P6 and Ortofon 2M Black cart. I blame this added sense of space to the crosstalk & delay inherent to vinyl playback, that and the extremely high quality of some vintage lacquer cuts from tape-not-digital. "Lush" barely describes the experience.

@thom_oz  exactly what I am trying to improve on. 

Not sure if your read the whole comment... @thom_oz 

The definition of 3D is getting a li’l blurred here. I have a couple of combinations of purist stereo, especially one built around a pair of tads that will do what you’re trying to describe and more.

Multichannel ’Object based’ 3D audio is a technology that only came around 2014 onwards for residential use and it is a different thing. It has nothing to do with channel based stereo or older/legacy ’channel based’ multichannel audio. The current proved-in upmixers for object based audio are 360 reality (Sony), Auromatic (Auro 3D), Neural X (DTS), DSU (Dolby) and a couple that are proprietary to Yamaha.

With the latter, it doesn’t matter what the quality of your recording was. A setup for object based would comprise of a minimum of 5 to 7 bedlayer speakers and 4 to 6 height/ceiling level speakers. This technology will pick up some trash stereo mix and discretize it, put it up as a sonic dome all around you, stretching from the perimeter of bedlayer+ceiling speakers and beyond. Sound engineers can also produce a object based audio mix for such formats, in which case you won’t need to upmix anything (considered a native mix),

When set up correctly, it didn’t matter that you had 9 or 11 speakers, all of them will disappear and you should feel like you’re floating around in a sonic dome/sphere. Sound objects will materialize and disappear, materialize/disappear, materialize/disappear anywhere in space inside this sonic dome....like ’flowers’ blooming and going away.....it’s called 3D.

"Hey, i got my almost 100 year old technology called stereo, but, now i have a muscle speaker and it is all 3D now"...doesn’t quite work like that. Some purist stereo streamer/dac manufacturers have some dsp "enhancements"/ soundstage tricks hidden away through FPGA, etc...didn’t matter, phase is off, etc and it is still limited by 2 speakers sitting up on the front stage.    

Why is this 3D not all that  prevalent? a simplifed answer is that it costs a lot, needs a huge room, steep learning curve, probably requires hiring a professional, etc...

@deep_333  why would you say:

"Setting expectations straight, 3D is a foolish concept concept in purist stereo." -?

I’m primarily listening to CD thru McIntosh MX-113 and a 2200 amplifier, and Sonus Faber Cremona speakers. My experience with this is 180 degrees opposite your assertion.

It is dependent on the recording quality (and most modern releases won’t cut it) but in my treated room listening to pop, jazz, classical and even some older electronic music I can get a massive sound stage with well-defined height, width & depth. Sometimes the center image seems to float behind the speakers and sometimes well on front of them. On many tracks a single element will sound like it’s behind the wall that’s behind my head.

The effect can be even more pronounced when listening to my (spotlessly clean) vinyl with a Rega P6 and Ortofon 2M Black cart. I blame this added sense of space to the crosstalk & delay inherent to vinyl playback, that and the extremely high quality of some vintage lacquer cuts from tape-not-digital. "Lush" barely describes the experience.