Swing, Shuffle and Groove

In a straight groove the two eighth notes inside a beat are equal. In a swung groove the first one is longer and the second arrives late. At the extreme the ratio approaches two to one, which is called shuffle and sounds like a triplet with the middle note missing. Most real music sits somewhere between the two, and the exact amount is a stylistic choice rather than a setting. Measurements of jazz drummers show something the textbooks usually leave out: the ratio moves with the tempo. At slow tempos it runs up to roughly three and a half to one, and at fast tempos it flattens toward one to one, which is to say practically straight. So swing is not a fixed triplet feel that you either apply or do not.

One groove at zero percent swing, then at twenty, then at forty, then at full shuffle. Same notes throughout, so the only variable is where the offbeats land.