0 th ▁century , ▁and ▁popular ▁music ▁throughout ▁the ▁ 2 0 th ▁century , ▁featured ▁" fixed ▁and ▁easily ▁disc ern ible ▁frequency ▁patterns ", ▁rec urr ing ▁" events , ▁often ▁periodic , ▁at ▁all ▁struct ural ▁levels " ▁and ▁" rec urrence ▁of ▁dur ations ▁and ▁patterns ▁of ▁dur ations ". ▁ ▁Mel od ies ▁in ▁the ▁ 2 0 th ▁century ▁" util ized ▁a ▁greater ▁variety ▁of ▁pitch ▁resources ▁than ▁ha [ d ] ▁been ▁the ▁custom ▁in ▁any ▁other ▁historical ▁period ▁of ▁Western ▁music ." ▁While ▁the ▁di at onic ▁scale ▁was ▁still ▁used , ▁the ▁chrom atic ▁scale ▁became ▁" wid ely ▁employed ." ▁Compos ers ▁also ▁all otted ▁a ▁struct ural ▁role ▁to ▁" the ▁qual itative ▁dimensions " ▁that ▁previously ▁had ▁been ▁" al most ▁exclus ively ▁reserved ▁for ▁pitch ▁and ▁rh ythm ". ▁K lie wer ▁states , ▁" The ▁essential ▁elements ▁of ▁any ▁mel ody ▁are ▁duration , ▁pitch , ▁and ▁quality ▁( tim bre ), ▁texture , ▁and ▁loud ness . ▁Though ▁the ▁same ▁mel ody ▁may ▁be ▁recogn izable ▁when ▁played ▁with ▁a ▁wide ▁variety ▁of ▁tim bres ▁and ▁dynamics , ▁the ▁latter ▁may ▁still ▁be ▁an ▁" element ▁of ▁linear ▁ordering ." ▁ ▁Ex amples ▁ ▁D ifferent ▁musical ▁styles ▁use ▁mel ody ▁in ▁different ▁ways . ▁For ▁example : ▁Jazz ▁mus icians ▁use ▁the ▁term ▁" le ad " ▁or ▁" head " ▁to ▁refer ▁to ▁the ▁main ▁mel ody , ▁which ▁is ▁used ▁as ▁a ▁starting ▁point