TK-949 said:

BTW another odd thing: The dianoga scene always had music, as long as I can remember, until 1997 with the SE the music was gone. But the GOUT didn't have the music either. For my version I'll add the music again.

After I read I this decided to check this on my german 1993 and 1995 Laserdiscs (can't check the 198 LD2, because my LD player can't play PAL analog audio). In both versions the music is present. However no other (english) version of Star Wars I checked has this music.

I checked rips of the following:

1982 US LD

1986 Japanese LD

1993 US DC LD

1995 US Faces LD

1995 French THX LD

2002 SE German TV broadcasts (Gkar)

2004 SE Offical DVDs german

2006 GOUT DVDs German and US

2 telecine bootleg copies of the pre 1981 release

Audio reconstructions of the mono and 70MM mix

Not a single one has any music in the scene with the diagona in the trash compactor.

So I am wondering what mix was the german theatrical sound mix based on?

I always assumed it was the dolby stereo mix because the german theatrical release also was in dolby stereo. The german version also had translations of lines that were missing in the original stereo mix but were present in the mono mix (C3PO's line about the power beams coupled in 7 locations).