Is soundstage just a distortion?

"I would assume that the acoustic effects of the pinnae (the part of the ear that is outside of the head) are a major contributor to the effect I described. "

I see. Could be the shape of the ear is a factor, larger area above to gather more higher frequency sound, less below.

Cupping the hands behind the ear is the best free tweak, after all. Maybe try that as a test with the tones and see?

If the room is lively, and a warble tone is used, I could see where reflected sound could be a factor, perhaps enough so for our sensitive ears to pick up on. Hard to say for sure.

PErception of higher frequencies coming from higher up than others is certainly not an unusual phenomena though I would say, whatever the contributing factors.

Traditional microphone techniques, both mono and stereo, do not encode significant height info.

Interesting article by John Atkinson.

I suspect that the ambient information contained in the recording, you know, the reverberant decay, echo, etc. is three dimensional; thus, on well recorded material the size of the venue is identifiable on a reasonably good home system as Carnegie Hall or Boston Symphony Hall, for example. Thus as one's system evolves, one should observe a better reproduction if the three dimensional ambient information, and a more accurate representation of the recording venue. One should be able, with some persistence, to get the perceived height of the soundstage to be the actual height of the room where the recording was made. Think of the soundstage as an expanding sphere. I can certainly understand if you've never gotten soundstage height you might be a little mystified.

The following provide tests, with which one may determine whether their system actually images, or reproduces a soundstage, as recorded. ie: On the Chesky sampler/test CD; David explains in detail, his position on the stage and distance from the mics, as he strikes a tambourine(Depth Test). The LEDR test tells what to expect, if your system performs well, before each segment. The Chesky CD contains a number of tests, in addition to the LEDR. (http://www.audiocheck.net/audiotests_ledr.php) (http://www.chesky.com/various-artists--jazz-sampler-amp-test-volume-1.html) The shape of your ears' pinnae is also a variable, regarding your ability to perceive images/locate sounds.

It's a little ironic that there are such things as records and CDs that test for soundstage since the soundstage you get is going to be limited by the, uh, limitations of the system you play them on. Kinda like seeing an ad for HDTV on your old fashioned 90s Panasonic. The HDTV picture quality in the ad is going to be limited by the constraints of the Panasonic. Wasn't Opus 3 another record label that "tested" for soundstage?