To apply mensural signs to a score you need to add a conventional time signature first, then modify its display by substituting with the appropriate mensural symbol in the Time signature properties dialog. Note that these signs are for show only; it is not possible to modify the duration ratio between different note values, and the actual underlying time signature remains unchanged.
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Early music, such as renaissance choral music, may be written without barlines or a time signature. This can be achieved in MuseScore as follows:
Note: In step 4 you can make the barlines invisible instead by selecting all and pressing V.
Note that the score still behaves as if measures are present. Measure properties can be applied if required.
Mensurstrich is a form of modern notation of early music in which barlines are drawn between staves rather than across them:
To indicate that a range of measures is to be strummed—but without indicating the exact rhythm:
Apply chord symbols in the usual way to the slashes.
Using beat slashes is a quick and convenient way of indicating strumming. The exact rhythm is left to the player and only the chord symbols play back.
To notate the chord slashes with the correct duration:
To notate the strum rhythm, with the option to include correct playback, you need to use rhythmic slash notation.