<P> This idea of directionality of beats is significant when you translate its effect on music . The crusis of a measure or a phrase is a beginning; it propels sound and energy forward, so the sound needs to lift and have forward motion to create a sense of direction . The anacrusis leads to the crusis, but doesn't have the same' explosion' of sound; it serves as a preperation for the crusis . </P> <P> An anticipatory note or succession of notes occurring before the first barline of a piece is sometimes referred to as an upbeat figure, section or phrase . Alternative expressions include "pickup" and "anacrusis" (the latter ultimately from Greek ana ("up towards") and krousis ("strike" / "impact") through French anacrouse). In English, anákrousis translates literally as "pushing up". The term anacrusis was borrowed from the field of poetry, in which it refers to one or more unstressed extrametrical syllables at the beginning of a line . </P> <P> In typical Western music 4 4 time, counted as "1 2 3 4, 1 2 3 4 ...", the first beat of the bar (downbeat) is usually the strongest accent in the melody and the likeliest place for a chord change, the third is the next strongest: these are "on" beats . The second and fourth are weaker--the "off - beats". Subdivisions (like eighth notes) that fall between the pulse beats are even weaker and these, if used frequently in a rhythm, can also make it "off - beat". </P> <P> The effect can be easily simulated by evenly and repeatedly counting to four . As a background against which to compare these various rhythms a bass drum strike on the downbeat and a constant eighth note subdivision on ride cymbal have been added, which would be counted as follows (bold denotes a stressed beat): </P>

When does the downbeat in a measure happen
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