Mixture stops are typically labeled with
Roman numerals with the number of ranks of pipes that they have, i.e. how many pipes sound when a single key is pressed. For example, a Mixture II contains two ranks (sounding two notes), a Mixture V contains five ranks, and so forth. The mixture is sometimes designed so that the number of ranks per note increases as one ascends the compass of the keyboard. A mixture exhibiting this trait is referred to as
progressive, and is labeled with two numbers (e.g. Plein Jeu III-VII, Fourniture IV-VIII). If a pitch is specified (e.g.
Mixture IV 2), it refers to the pitch of the lowest-sounding rank when the lowest C on the keyboard is pressed. Sometimes a mixture is labeled with multiple numbers denoting the intervals above root pitch that it will sound. For example,
Mixture 15.19.22.26 means when a note is pressed, the intervals of a 15th, a 19th, a 22nd and a 26th will sound (or 2' + 1' + 1' + ').
Types of Mixtures Fourniture This is the most common type of mixture, often written simply as "Mixture". It contains octaves and fifths and is usually progressive. It is complementary to the Cymbale mixture.
Cymbale A relatively high mixture containing, properly, octaves and fifths, but may include the major third. It accompanies the Fourniture to create a full chorus mixture sound.
Plein Jeu Literally "full chorus" this is usually a combination of the Fourniture and Cymbale mixtures.
Scharf A high-pitched mixture (1', 1/2', or 1/4') usually of III or more ranks=mIV, IV-V, III-IV, V-VI. It contains octaves, major thirds (at least one), and fifths, though it can also contain the minor seventh.
Rauschquint A harmonic mixture containing two or three or more (IV/V/VI/VII/VIII/IX/Rauschquint III-XII ranks of only octaves and fifths. ==Variables affecting tone color==