Originally Posted by SoundChex
In what I suspect is now a 'somewhat dated
' article on creativePLANETnetwork com "Big Enough for Everest: Inside IMAX Sound" (link)
there is some useful exposition on the use|content of various IMAX speakers|channels--including the center overhead--
with reference made to differences from non-IMAX
speaker configurations. With respect to 6th channel overhead sound:
Which reinforces what has always been true: Sound should come from a speaker when needed, not continuously, just because there is a speaker there!
I was to the Tuttleman IMAX Theater @ the Franklin Institute in Philly on Monday (Thanks to forum member airscapes recommendation) and saw Space Junk (though not in 3D since it was an OMNIMAX).
They employed the 6th speaker above the LCR but used it sparingly. See the image below.
I don't think any modern conversion outside of a science type location (read: AMC, et al, retrofits) have the 6th channel installed since they don't play the documentaries that take advantage of them.
I wonder how these other theaters who now compete, not just in size of screen but also audio (and maybe surpass IMAX in this regard) are hurting IMAX's bottom line.