Apparently these budget releases from Documents suffer from poor sound quality...
"Label imprint of German budget label Membran. Quality of their releases varies a lot. Their mid-2000s compilations and box sets are miserable. Due to poor sources (possibly mp3s?) and awful mastering, sound quality is horrible. These releases are marred with audible sizzle, excessive echo and distortion. I'd strongly suggest to avoid these older titles.
However, quality of their releases has improved during the time. Their mid 2010s box sets are actually pretty ok. Sound quality is definitely better than before. Most blatant issues have been fixed. Although these newer releases are still far from audiophile standards, they are not terribly defective either."
although, on this particular release, no such problems, sound quality is good.