Niko Wilke found these speakers in Germany built by Schoenbohm, here is the short story of Niko:
I found these speakers with Monitor Gold 15" in "audiolive Schoenbohm" enclosures. This German company used to build studio equipment in the 70s. The enclosure is 140 x 60 x 40 cm. The back panel (and thus the ventilation surface) can be adjusted simply be turning the "Flügelmutter" (don't know the English term for this type of nut). Best regards! Niko.
