Audsley lists Grossquintenbass with this description: This name is given to a covered stop, of 21-1/3 ft. pitch, inserted in the Pedal of the Organ in the Cathedral of Bremen [Germany]. The stop strictly belongs to the 64 ft. harmonic series, and was evidently introduced with the view of producing the acoustical differential tone which we have termed Vox Gravissima. This fine organ of 59 speaking stops, was built by Schulze, of Paulinzelle. Interestingly, Hopkins & Rimbault cite the same stop by a different name: �in the Cathedral organ, at Bremen built by Schulze is a �Quintet Bass� of 21-1/3 feet tone, of stopped wooden pipes.� According to Osiris, the Schulze organ in Bremen, built in 1847-9, was replaced in 1894 and no longer contains a stop by any name at 21-1/3' pitch. We have been unable to determine the actual name of this stop, and no other examples of Grossquintenbass or Quintet Bass are known. Adlung also lists Grossquintenbass, but says only �at G�rlitz there stands a Grossquintenbass [6']�. Irwin lists it as a synonym for Sub Quint, but this is not strictly correct, as the �bass� suffix indicates a pedal stop which would not properly appear in the manuals.