An 8' open wooden flute, invented by Hope-Jones and first used in the Church of St. John, Birkenhead, England. The Tibia Plena is of very large scale, with the mouths on the narrow sides of the pipes, featuring moderately high cut-ups, leathered upper lips, and sunken blocks. It speaks on wind pressures of 4" and greater. Bonavia-Hunt calls it a large-scale Clarabella. The name comes from the Latin tibia (�pipe�) and plenus (�full�). Audsley describes its tone as considerably rich, �singularly full and dignified�, and names it the most powerful unimitative wooden flute. Wedgwood calls it the most powerful and weighty stop of the Tibia family, and says: A curious acoustical phenomenon is sometimes to be observed in connection with this stop, for in the immediate neighbourhood of the pipe a faint undertone, one octave below the normal pitch of the pipe, is often apparent. The cause of this has not yet been expounded. According to Bonavia-Hunt, Hope-Jones �claimed that it provided a 16ft. effect in addition to the unisonal foundation�. Bonavia-Hunt speaks disparagingly of the Tibia Plena, saying that it �was most objectionable in close chords: its flutiness was far too intense. It hooted through every combination of which it formed an ingredient.� Irwin describes it as a �loud Flute-Diapason hybrid of stentorian proportions�, and says �not all of the modern examples have the fluty, cloying tone of the earlier ones; many are more brilliant and less intense�. Wedgwood reports that the names Tibia Major and Major Flute have been used for this stop, and the name Tibia Plena was also used by Hutchings-Votey for a large-scale metal flute.
Tibia Plena 8', Solo; Tibia Plena 16', Pedal; Auditorium, Ocean Grove, New Jersey, USA; Hope-Jones 1907. (This stop was probably a later addition.)