It's too bad that a number of the tracks have such bad sound problems on them. At one point I was going to try and repair these damaged tracks so that a more complete version of the soundtrack could be included on the FanFiltration edit of DUNE DVD set as an extra. Thing is, that I just ran out of time on the project.
Here is an informative link to a review of the two known DUNE Soundtrack CDs by TOTO. There is also info about the sound problems found on the extended version CD put out by PEG.
Filmtracks Editorial Review: DUNE
FF