Phantom sound - boxed, dipole etc?

[Divasson]

It behaves like a point source, and having no corners has less diffraction error than conventional speakers.

An accurate reproduction of height is not possible with a stereo pair of speakers, and if you get one it will be an artefact due to imperfect speaker performance.
2 speakers = 2 dimensions accurately reproducible, and these are width and depth, both of which are truly exceptional on the Phantoms.

My engineering/math background tells me the same thing, and yet... I clearly hear things on top of my head on some records. I am using Gallo Strada loudspeakers, that have a tweeter that behaves like omnidirectional, and two ball-shaped 4" drivers. In Extreme's "Warheads", there is an airplane flying from front left to back right, on top of you - clearly audible (and yes, there is an improvement with firmware 8.0.0, also in height). In Chesky's 5.1 Surround Show, stereo CD layer, track 6, "The Storm", the thunders are clearly heard overhead. There is no mistaking it!

In fact, there is a series of articles in The Absolute Sound from Charles Zeilig, Ph.D., titled "New Methods for Quantifying Sonic Performance" (TAS 246, 248 and 249), where he sets a system playing a piece with some voices heard over your head (LIM K2HD 040, UD, track 5, "Misa Criolla"), and sets up a system whereby he measures the height of the apparent voice in inches measured on a given plane, with the help of an assistant, for different combinations of equipment, cables, codecs and other tweaks. Results, according to him, are repeatable and measurable.