Sedecima (unknown) Sedetz[e] (unknown) Sedex (unknown)

Adlung lists these names with the following description:

Sedetze, Sedex, Sedecima, are indeed all the same, and are derived from Sedecim, "sixteen". Accordingly, if one were to proceed upward [from C] for 16 diatonic notes, one would end up not on c['], but on d['], or a second above c['], which does not sound [well] on the organ . Thus it is clear that this must be a mistake in the figuring, and that Sedecima is written instead of decima quinta [i.e., fifteenth]; for it is supposed to be an octave stop, because it is at 2' and 1'. The size of the Sedecima is in proportion to that of the Principal; with a 4' the Sedecima is 1', with an 8' it is 2', and with a 16' Principal it is calculated at 4'.
...
Sedex is the same thing by origin; although Niedt in the second part of his Handleitung, first edition, chap. XII, presents it as a Sesquialter, Mattheson in the second edition nevertheless corrects him by saying expressly that it is a little Superoktave at 1' or 2' pitch. The name "Sedetze" appears in Praetorius when he deals with Oktaves . Yet according to correct calculation it ought always to be called quinta decima, or Quintez for short.

Grove describes Sedecima as follows:

A term found in Habsburg Europe of the 17th and 18th century to denote a 1-1/3' Sifflote.
Throughout its period of popularity, [Sifflöte] could be either 1' or 1-1/3', somebuilders preferring the first, others the second. Much the same was true of the Sedecima, the Sifflöte of Habsburg countries.

Williams supports Grove's description. Maclean, however, calls Sedecima “an old name for Fifteenth”.

Examples

All known examples are given below. No examples of Sedex are known. Contributions welcome.

Sedecima 1', Rykpositiv; Cathedral, Roskilde, Denmark; Rottenstein-Pock 1555, Maas 1611, Lorentz 1655.

Sedecima 1', Hauptwerk; Teinkirche, Prague, Czechoslovakia; Mundt 1673, Gartner 1823.

Sedecima [no pitch given], Manual I; Valtice Parish Church, Valtice, Czechoslovakia; Hencke 1750, Doubek 1994.

Sedecima 1', Chorpositiv; Grossmunster, Zurich, Switzerland; Metzler 1958.

Sedecima, Manual I; Parish Church, Valtice, Czechoslovakia; Hencke 1697.

Sedecima 1', Positiv; Wallfahrtskirche Maria Kirchbüchl, Vienna, Austria; Hencke 1750.

Sedecima 1', Rückpositiv; St. Michael, Vienna, Austria; Sieber 1714.

Sedetz 1, Brustwerk; St. Cosmae, Stade, Germany; Schnitger 1668-75.

Bibliography