hi Bruno,
Let me end this mystery ...those began life as Jensen Imperial back loaded corner horn cabinets. It is a 1950's design. They could be bought from Jensen as kits and put together or prebuilt. They could be loaded with a large number of different Jensen speakers. Somewhere along the line someone put a board across the top basshorn exit and put Klipsch mid and tweet drivers there and added a Klipsch crossover. They also cut a round hole in the front of the cabinet for a midrange, that is not in the original plans. The round whole at the bottom was for a 15 in. woofer which rearloads the basshorn. The plans for these are on the internet, just google Jensen Imperial corner horn. This WAS NOT a Klipsch designed cabinet.