Centered beams are beams that are vertically positioned between notes within the same beamed group, with stems for notes above the beam pointing downwards and stems for notes below the beam pointing upwards.
Centered beams are also known as “kneed” or “elbowed” beams due to their often angular shape.
When a beamed phrase spans a large pitch range, normal beams are often positioned very close to some notes in the phrase but very far from other notes in the phrase, making some stems very long. Having a centered beam in a phrase that spans a large pitch range can reduce the maximum distance between noteheads and the beam, but can also place the beam within the staff, which can obscure staff lines.
By default, Dorico Pro allows beams that include notes on both sides of the middle staff line to appear centered. You can also create custom centered beams for beams that include notes only on one side of the middle staff line.
To center beams between the staves of grand staff instruments, you can create cross-staff beams.