▁stack ▁is ▁a ▁combination ▁of ▁two ▁or ▁more ▁c ym b als ▁mounted ▁in ▁contact , ▁producing ▁a ▁sound ▁unlike ▁any ▁single ▁c ym bal . ▁The ▁effect ▁is ▁similar ▁to ▁a ▁lo os ely ▁closed ▁hi - hat , ▁or ▁can ▁altern atively ▁be ▁seen ▁as ▁an ▁extreme ▁case ▁of ▁a ▁s izz le ▁c ym bal ▁with ▁the ▁upper ▁c ym bal ▁serving ▁as ▁a ▁single ▁large ▁j angle . ▁The ▁exact ▁effect ▁is ▁dependent ▁on ▁the ▁t ension ▁on ▁the ▁mount ing ▁b olt , ▁and ▁with ▁some ▁combinations ▁can ▁be ▁varied ▁from ▁a ▁very ▁short ▁cr unch ▁to ▁a ▁much ▁longer ▁bu zz . ▁▁▁▁ ▁This ▁technique ▁was ▁pione ered ▁by ▁Dave ▁We ck l , ▁Mike ▁Port no y ▁and ▁others , ▁originally ▁using ▁a ▁ch ina ▁spl ash ▁as ▁the ▁upper ▁c ym bal . ▁Port no y ▁mounted ▁both ▁c ym b als ▁bell ▁up , ▁with ▁no ▁spacing ▁felt , ▁to ▁maxim ize ▁contact ▁between ▁them , ▁and ▁choosing ▁c ym b als ▁of ▁sufficiently ▁different ▁profile ▁to ▁ensure ▁that ▁the ▁contact ▁was ▁not ▁enough ▁to ▁cho ke ▁them ▁completely . ▁ ▁As ▁the ▁technique ▁became ▁established , ▁c ym bal ▁mak ers ▁introduced ▁special ized ▁stack ▁c ym b als ▁designed ▁specifically ▁for ▁use ▁in ▁stack s . ▁However ▁the ▁older ▁technique , ▁using ▁a ▁ch ina ▁spl ash ▁on ▁top ▁of ▁a ▁crash , ▁ch ina ▁or ▁another ▁spl ash , ▁also ▁remains ▁popular . ▁ ▁Stack ing ▁should ▁not ▁be ▁confused ▁with