Bar length

Bars usually last the same duration and start and end at the same positions for all players. However, some music involves bars of different lengths coinciding, and there are situations where some players may have no bars indicated at all.

You can change the duration of a bar by changing its time signature or, in music in open meter, by inputting barlines where required. You can hide time signatures you do not want to show in the music; for example, if you are writing music with an irregular meter and you require barlines only to group material together, but not to imply any sense of meter.