Mixture (organ)
Organ stop with several pipes per key that reinforces the overtones.
What it means
The mixture is an organ stop in which a single key sounds several pipes at once, usually several ranks at intervals of octaves and fifths. It reinforces the high overtones of the sound. The stop is not drawn on its own but together with the foundation stops, such as the principal.
A mixture usually has three to six ranks or even more. So that the high pipes do not become unpleasantly shrill, the mixture "breaks back" in the upper registers of the keyboard: at certain notes the ranks jump down an octave or a fifth. This is called repetition.
Musical use
The mixture belongs to the plenum, the full chorus of an organ, and is especially characteristic of baroque organs. It gives the sound brilliance, edge and transparency and helps to make polyphonic lines clear even in the full chorus. Related stops are the cymbal and the scharf, which lie higher and brighter.
The mixture should be distinguished from mutation stops such as the twelfth or tierce, which individually supply a particular overtone and alter the sound without being part of a compound. The mixture is understood as the crown of the sound above the 8' and 4' stops.
Performance practice
As an organist you draw the mixture together with the foundation stops and pay attention to the interplay with the reeds. In the full chorus you do not hear the individual overtones but brilliance. Use it sparingly if the acoustic of the room is reverberant.