A short piece of 'Rubycon' can be heard in the film: in the scene where they found that "evil had been spread on the village" in the background, the spooky choir part from the side 2 of 'Rubycon' can be heard: it's the part just before the sequencers came in.Rubycon nothing to do with the Keep
There are many pieces from Logos and also, what is known as 'Moorland' (form ''Miriam -Tatort" single) can be heard.
I think that TD had a hand in the audio effects of the film, apart the soundtrack, but maybe that's a theory of mine