A tempo change
A tempo is a modifier that, once placed on a staff inside a score, changes the speed at which the score is played from that point on.
General tempo[]
A score can contain two types of tempo settings: a general tempo which applies to all the score, and which can be set from within the score menu, or an unlimited number of tempo changes, which are added manually with the tempo tool.
The tempo edit dialog[]
To insert a tempo change on the score, click the tempo tool on the "Ottava, tempo & pedal tools" palette, and click anywhere on a staff. The tempo dialog will now be displayed on the screen, allowing you to specify a number of tempo settings.
The tempo edit dialog
At the top of the window, there is a caption field, for adding the tempo change a name. Filling the caption box with text does not necessarily remove the original tempo indicator. This box can come in handy for writing tempo instructions like Grave, Presto, Accelerando, Morendo, etc.
To specify the actual tempo, pick a note value from the next frame, and write a number in the "=" box. This means that n notes with the given value, with n being the given number, will fill one minute. For example, choosing the fourth note as note value and 90 as tempo value will make 90 fourth notes fill a minute, and therefore one fourth note equal to 60/90=2/3 of a second.
The next few settings are related to graphical aspects of the tempo change. There is a slider for scaling the symbols (works for captioned tempo changes too), a switch between fully hiding the tempo values or showing them at the left or right of the bounding box (after the caption if present), an option to display a line after the tempo change, until the end of the bounding box (probably suitable for situations like an accelerando, where continuity is needed). The, the tempo can be shown or hidden with the "Print" checkbox.
The smooth tempo change parameter (referring to gradual tempo changes), if enabled, activates a number of controls. The "Begin" and "End" fields control the region that should be affected by the gradual change (speeding or slowing), by the use of bars, beats and cents of beats. Lastly, a variation graph allows you to graphically edit the tempo change speed.