Muta
Direction for wind or percussion players to change the tuning, for example for timpani or horns.
What it means
Muta (Italian for "change") is a direction in orchestral parts telling the player to retune the instrument. It appears most often in timpani parts and reads, for instance, "Muta in G–D": the two drums are tuned to new notes. In parts for natural horn and natural trumpet it means a change of crook or tuning, for example "Muta in E flat".
Musical use
The direction is found in orchestral music from the baroque to the Romantic period, when instruments still had no valves or pedals, and requires the player to retune during a rest. Often little time remains for this, which demands care and a good ear.
It should be distinguished from transposing, where the player merely reads differently while the instrument stays the same, and from tuning in the sense of a basic pitch: muta concerns the actual changing over.
Performance practice
At a muta, check the new tuning at once quietly by ear against a reference note. Plan the retuning in rests without disturbing colleagues, and practise it in rehearsal so that you are secure in the concert.