How did they do that?

I was listening to the new Annie Lenox CD, "Bare", when cut #3, 'The Hurting Time' came up - all of a sudden, I'm hearing the music behind me - with my 2ch system. I actually turned around wondering if someone installed speakers in the back of my room w/o telling me. This phenomena only existed at the beginning of this one song on the. Any ideas? An inquiring mind needs to know. Thanks!
Probably the recording switched out of phase between the channels. This can give the illusion of something coming from behind as it makes it very difficult to pinpoint the source.

Or it cold be some other trick.
Q sound, maybe, or the Spatializer, used in the production process. I find some Prince tracks do those tricky things where you notice something is moving in unexpected directions. I believe but don't know for a fact that these are phase tricks. Cool, though!

Best regards,

Bob Wood
The very end of Pink Floyd's darks side of the moon does that as well. I have a number of recordings that do funky stuff like that, I must admit it is quite amazing!
It's called colorless reverberation. Manfred Schroeder of the old Bell Labs was the guy who understood it. I don't know enough physics to answer your question but you might find an explanation on line from a Schroeder treastise.(Schroeder was the guy Avery Fisher gave a wheelbarrow full of money to fix the acoustics in what is now called Avery Fisher Hall at Lincoln Center.)
Out of phase. If you had a speaker bridged across your stereo amp, or some other way of listening to the out of phase component of the signal the effect would be more dramatic. This is matrix multichannel.
And I thought it was something special that only Avalon Speakers can do.
Pragmatist - thanks for the link and the explanation. I now remember why I didn't do well in physics class.