▁In ▁swing ▁rh ythm , ▁the ▁pul se ▁is ▁divided ▁une qu ally , ▁such ▁that ▁certain ▁sub div isions ▁( typ ically ▁either ▁e ighth ▁note ▁or ▁six teenth ▁note ▁sub div isions ) ▁alternate ▁between ▁long ▁and ▁short ▁dur ations . ▁C ertain ▁music ▁of ▁the ▁Bar o que ▁and ▁Class ical ▁era ▁is ▁played ▁using ▁notes ▁in ég ales , ▁which ▁is ▁analog ous ▁to ▁swing . ▁In ▁sh uffle ▁rh ythm , ▁the ▁first ▁note ▁in ▁a ▁pair ▁may ▁be ▁twice ▁( or ▁more ) ▁the ▁duration ▁of ▁the ▁second ▁note . ▁In ▁swing ▁rh ythm , ▁the ▁ratio ▁of ▁the ▁first ▁note ' s ▁duration ▁to ▁the ▁second ▁note ' s ▁duration ▁can ▁take ▁on ▁a ▁range ▁of ▁magn itudes . ▁The ▁first ▁note ▁of ▁each ▁pair ▁is ▁often ▁understood ▁to ▁be ▁twice ▁as ▁long ▁as ▁the ▁second , ▁imp lying ▁a ▁triple t ▁feel , ▁but ▁in ▁practice ▁the ▁ratio ▁is ▁less ▁definit ive ▁and ▁is ▁often ▁much ▁more ▁subt le . In ▁traditional ▁jazz , ▁swing ▁is ▁typically ▁applied ▁to ▁e ighth ▁notes . ▁In ▁other ▁gen res , ▁such ▁as ▁fun k ▁and ▁jazz - rock , ▁swing ▁is ▁often ▁applied ▁to ▁six teenth ▁notes . ▁ ▁In ▁most ▁jazz ▁music , ▁especially ▁of ▁the ▁big ▁band ▁era ▁and ▁later , ▁the ▁second ▁and ▁fourth ▁be ats ▁of ▁a ▁ 4 / 4 ▁measure ▁are ▁emphas ized ▁over ▁the ▁first ▁and ▁third , ▁and ▁the ▁be ats ▁are ▁lead - in — main - be