Listed only by Irwin, who says: A Foundation stop of 4' on the manuals, creating the Octave's tone from double-length open metal pipes. It is moderately large in scale and loud in tone, although not brilliant or shrill. Like all harmonic open metal pipes, it is inclined to a round flutiness rather than an edgy or hard tone. It is not intrusive in combination and blends well with loud unisons of all sorts. Two or three ranks of 4' Diapasons all speaking together are generally considered to be superior to this stop in tone, although more expensive.