Understanding Ad Libitum in Music Performance

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In sheet music, ad libitum is often abbreviated as "ad lib." and in the Latin means "at one's pleasure." Other terms that might be used in music notation with a similar expression are the Italian a piacere or the French à volonté

Definition and Examples

Playing ad libitum can mean a variety of things in music performance. Understanding the right meaning for each circumstance helps musicians to execute the indication correctly depending on its context.

  1. In reference to tempo, this can mean that a performer can play the passage in free time rather than a specified tempo. A musician might slow down or speed up a passage according to their artistic preference.
  2. When ad libitum is used in melodic improvisation, it typically means that the musician can improvise the melodic line of a passage. This does not mean that the harmony for the passage is altered, however, and the musician's melody must fit within the existing harmonic structure of the passage.
  3. For a piece with more than one instrument, ad lib. can mean that the instrument is optional and may be omitted for a section. Typically this occurs when the instrument that is optional not an integral part of the harmony or melody. Sometimes this might be seen in a piece written for strings when there is a first, second, and third violin part as well as a viola and cello part. The third violin might contain several ad lib. sections (or even be entirely optional). 
  4. The phrase "repeat ad libitum" means to play a passage as many times as the performer desires; so instead of repeating a passage once, the musician may desire to repeat it three, four or five times, and sometimes if it is at the end of a song, repeat, and fade-out. 

The term ad lib. is not as frequently used as some other music expressions, but it is certainly a good idea to understand the various uses of the term when reading and performing music.