Spitzflöte, Spire Flute, Flûte à Fuseau
These names, of which Spitzflöte is by far the most common, denote an open flute stop whose pipes are conical in form, as shown by Audsley's illustration reproduced here. While this pipe form is a common one, dating back to the late 15th century (according to Grove), it is not always clearly evidenced by the name on the stop control.
The amount of taper has varied considerably, with the top diameter being as much as 3/4 or as little as 1/5 the diameter at the mouth. According to some sources, the English have typically used a gentler taper than the Germans. The pipes are usually tuned by means of large ears. The stop is nearly always made of metal, though pyramidal wood pipes have sometimes been made, usually for the 8' octave.
Tonally, the Spitzflöte is usually classified as a Flute/String hybrid, and occasionally as a Flute/Diapason hybrid. Its tone has been described as reedy or breathy, and blends very well. It has been made at every pitch from 16' to 1', including mutations; indeed, tapered pipes are frequently used for mutations because of the excellent blending quality that can be obtained. The most common pitch for the Spitzflöte is 4', with 8' being only slightly less common.
This stop has much in common with the Gemshorn, so much so that it is sometimes difficult to distinguish between their pipes or even their tone. Most sources, though not all, give the Spitzflöte a sharper, more pointed taper than the Gemshorn. The Gemshorn is often slotted, whereas Audsley warns that the Spitzflöte must never be slotted. The Spitzflöte typically tends more toward flute-tone than the Gemshorn.