Irwin describes Double Gemshorn as follows: A Foundation stop of 16' manual pitch, and 32' pedal pitch. The 32' manual form also exists in a few organs. It is the proper bass for the Gemshorn Chorus, and its luminous, clean-toned chord of lower-pitched harmonics is sometimes preferred to the Double Diapason of heavier quality. It blends unusually well with all manual combinations. Its long pipes are conical, rather than cylindrical like the Diapasons, but are sometimes made of wood. While Irwin lists Gemshornbass as a synonym, the German suffix bass indicates a normally pitched rank that appears in the pedal.
No examples of Double Gemshorn are known. Contributions welcome.