why 3D Holographic sound

That's happened on my system--something I noticed even back in the 80's with much different gear. I believe the main culprit is sound reflected from the side walls and perhaps the ceiling and floor. It can be remedied to some extent--perhaps a large extent--by adjusting toe-in and tweeter angle. (I think it's 90% a tweeter issue.) Also, if your room can tolerate it, a lot of acoustic treatment can probably make a big difference.

But even when I've got everything just right and have very nice imaging from my listening chair, there seems to be a sweet spot fairly near the speakers and above them (i.e., that I get from a standing position) where the imaging is particularly fine. (The spot that I vividly remember with my Dahlquists in the 80's was only about a foot away.)

Two likely issues. One is the vertical dispersion of the tweeter is different for your standing and sitting positions. You might try changing the tilt of the speakers if possible.

The other is the reflected sounds probably differ between standing and sitting. Look for differences in the first reflection surfaces (left, right, up, down and even behind) between standing and sitting. Strong reflections will muddy the image. Changing speaker position or adding sound absorbing materials at critical points may help.

You'll probably have to experiment to find a solution, but it will probably be centered around a factor noted above.

depends on what you're sitting on. a high-back chair with a cushion by your ear will of course sound very different than a shorter chair with nothing immediate by your ear absorbed or reflected

I have speakers tilted up about 2" and about 7 feet apart, and 3feet from back wall, my room is about 12x17' and carpet floors,using VR3s' speakers,kown to cast a preatty decent sound stage,just replace my VTL 5.5 for a joulet 150mk11, though was my preamp, was wrong,need to find a solution,when standing the sound and imaging is absolutly Gorgeous, will try difusing panels, next:

"I have speakers tilted up about 2""
There's your problem.

HI, thanks, Etran, will try leveling speakers, will get back to you with the results, thanks: and by the way,upgraded from VTL, to joulet 150mk11, ans boy what a diference; much more resolving, and organic sound, upgraded due to imaging problem, was a win,win, situation in my case:

I think Etran and Shadowshaman nailed it. Especially the 2" tilt. Take that away and your stage height will definitely drop down a bit. The best part is that it's FREE!

-RW-

I had a similar problem with my VR4JRs and resolved with tweeter diffraction devices offered by DifFraction be Gone at:
http://www.stereomojo.com/Diffraction%20Be%20Gone%20Review/DIFFRACTIONBEGONEREVIEW.htm
The are essentially pressed wool felt pads that surround your tweeter drivers. I tried to make my own but could not find the correct material online or locally.
I am in no way connected to this company. I tried their money back offer and will not be sending them back because they really tightened-up image placement. It is a solution incorporated in many off-the-shelf products such as Dunlavy speakers and a few others.

3 dimensionality has to do with reproducing the sound waves while retaining the phasing of the live performance. Wall/cieling,floor,reflections will fill in and confuse the compressions and rareractions, and ruin the 3 -D effect.

Do you have a headrest or is your head unobstructed from the back when seated? I find a headrest interferes with imaging and depth, though seems to increase perceived bass.

Regards,
Will

If you wear glasses....remove them for best sound. They resonate