[Carl V]

Why do most speakers have a problem with the vertical sound stage or imaging?

Ambisonics has made a big to do about this as has other respected "A" chain &
"B" chain engineers.  Chesky and others have thought that we need an UP channel.
I've heard a few custom demos where there were UP channels or like DSP Meridian
set-ups with yaw & tilt adjustments (and an extra speaker)....impressive to say the
least.

This is obviously a variation of soundstage width & depth.
I just thought I might separate the two phenomena.
 

[Scotty]

Supposedly the sensation of vertical imaging within the confines of a stereo system is an artifact of which results from the way we are predisposed to assign a direction to sounds which are reproduced in a certain fashion. In otherwords there are those who say it is all in our head. Cheskys' ability to produce a CD which
has information that when properly reproduced exhibits height with
specific locations and direction seems to indicate that information that we percive as a dimension of height is also within the control of the recording engineer and subjection to manipulation even if it is all in our heads. In my experience speakers with simpler crossovers that are phase correct with good high frequency resolution and wide dispersion seem to reproduce an image with a definite vertical
component as well as width and depth.  The ability to reproduce an image with height as well as depth and width is one of the things I look for when evaluating a loudspeaker. A loudspeaker that does well this can be laying on it's side on the floor and still put an image near the ceiling. Once again of course, this information can also be lost in inferior equipment upstream of the loudspeakers.
Scotty