Here is an MP3 comparison of the Wampa scene.
http://www.4shared.com/mp3/hUnu5EyA/Wampa_comparison.html
It begins with the scene from the 70mm in-theatre recording, followed by the 1985 BetaHifi tape. Then I put the two in sync - 70mm in right channel, 85 tape in left - which results in a nearly six-second gap.
David