The concert may have had 2 speakers in the front for amplification/reinforcement , but the sound from those 2 speakers bouncing off the side and rear walls provided the "rear surround channels" ambience. There's no way you could have heard the concert in 2CH, unless you had sound absorbing material 2/3's surrounding your head! Even then, it really would have been 3CH (LCR).
Sorry, but there are no rear or side walls at all. The roof is some sort of suspended tarpaulin material.
Here is an actual image of the Pavilion:
If we assume that the instruments can be also heard directly and that sonic reflections also bounce from those instruments off the back stage wall, then I'll allow for a type of bi-polar speaker type reflections or possibly 3 front channels??? Nah. It sounds like plain jane stereo to me.
Hope this picture clears up your confusion.
Now, if the concert was in the Compaq Center, then I'd say that with wall reflections making every note a distorted mess, it IS more like a bad surround mix. IMO, there is nothing more artificial sounding than a multichannel mix where instruments start to play behind you.
I guess from anywhere beyond those uncovered seats, the effect would be pretty monaurial anyway.
Matthew: in fact each one of the poles halfway up the lawn have speakers on them and they broadcast a mono signal. However, they are pointing up the hill, not back into the seating area.
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Take Care,
merc
[This message has been edited by merc (edited July 18, 2002).]