Link 1:  This link describes what has been referred to as the "Hafler Hook-up".  David Hafler, a top audio engineer of the late 1960's and 1970's came up with this simple circuit.  (Read carefully before you start grabbing alligator clip leads).  I have had fun experimenting with this simple surround sound gimmick:

http://sound.westhost.com/project18.htm

Link 2:  Michael Gerzon . . U.K. audio pioneer.  This is a more lengthy history of "spatial sound" technology during a similar time span as Hafler . . This article is quite lengthy but incredibly interesting to an audio techy.  Gerzon was definitely "ahead of the curve".

http://www.michaelgerzonphotos.org.uk/i...oneer.html

Cheers . . . Lanny

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In many cases in 5.1 if something go from the righ to to left top, the sensation is that the sound go through the head, and not above it.
They created some special mics to try to fake it.

Anyway you cannou change the lateral inclination angle of your head (line between left to right ear).

It's a good sound system if you have a fine speakers and amplification.  But it's not true 3D.

If it was really true 3D, why they are working in a 22.1 system?????

After all 3D need 3 dimentions, and 5.1 and 7.1 all have only 2 dimentions, cause there is no speakers on the ground or in the roof.

But the sound dissipates and disperses and it's possible to simulate sounds coming from the roof or the floor.

Would be a advantage to include 7.1 sound for pianoteq ?

Or for piano 7.1 is not very relevant compared to 5.1 ?

According this video 7.1 is superior:

http://www.youtube.com/watch?v=LQ6X8Ruials

Anyway, I do not know why they call 5.1 or even 7.1 as 3D sound.
After all 3D need 3 dimentions, and 5.1 and 7.1 all have only 2 dimentions, cause there is no speakers on the ground or in the roof.
It's a very good system, but not really true 3D.