Audsley lists this stop with the following description: A mutation stop of the Tuba class, of 5-1/3 ft. pitch, voiced to yield a tone considerably softer than that of the unison Tuba (8 ft.) in the same division. As it strictly belongs to the 16 ft. harmonic series, it can only be properly introduced in association with the Contra-Tuba, 16 ft. The complete family will accordingly comprise the Contra-Tuba, 16 ft.; Tuba, 8 ft.; Tuba Quint 5-1/3 ft.; and Tuba Clarion, 4 ft.; - a series of powerful lingual stops capable of producing compound tones of surpassing grandeur. We know of no Organ in which the complete family is introduced. Irwin also lists it, saying: A Chorus Reed of 5-1/3' on the manuals, and 10-2/3' on the pedals. These pitches are the third harmonics of the sub-unison series of stops. They should be drawn with powerful Chorus Reeds of 32' on the pedals, and 16' on the manuals. Such pitches as these, speaking from loud Reed pipes, are useful in filling up the tone of a large Reed Chorus with unusual brilliance. They are proper only in the acoustical environments that can absorb them, needing at least the 1.8 seconds of reverberation that are considered by experts to be the ideal for music.