Thanks. I think treewind's definition must apply, because the sampled instruments sound very real. The tape is dated 1995.
The pieces are so complex and natural-sounding that I suppose the performers went to the studio, one of them sat at the keyboard, turned on the krumhorn button (for example) and played with the others.
That makes me feel better than to think that they just did the simple parts and told a technician to add on the unusual instruments, as if applying a Post-it note.