Understanding note-value ratios

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Durations and signs

Whole, half, quarter and eighth notes express relative durations. A half note equals two quarters, and a quarter equals two eighths. These relationships alone do not specify seconds; tempo and the selected beat unit do.

Choose the beat unit before counting. A half note spans two beats when the quarter is the beat, but one beat when the half note is the beat. Keeping ratio and tempo separate helps when changing meter or comparing different notation styles.

Example

At quarter=60, an eighth lasts 0.5 s; at quarter=120 it lasts 0.25 s.

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How many eighth notes equal a whole note?

Related topics

References

Music Theory for the 21st-Century Classroom

Subject-expert review pending.