▁either ▁composition ▁or ▁listening . ▁ ▁The ▁first ▁phase , ▁known ▁as ▁" free ▁at on ality " ▁or ▁" free ▁chrom atic ism ", ▁involved ▁a ▁conscious ▁attempt ▁to ▁avoid ▁traditional ▁di at onic ▁harm ony . ▁Works ▁of ▁this ▁period ▁include ▁the ▁opera ▁W oz ze ck ▁( 1 9 1 7 – 1 9 2 2 ) ▁by ▁Alban ▁Berg ▁and ▁Pier rot ▁L una ire ▁( 1 9 1 2 ) ▁by ▁Sch o enberg . ▁ ▁The ▁second ▁phase , ▁begun ▁after ▁World ▁War ▁I , ▁was ▁exempl ified ▁by ▁attempts ▁to ▁create ▁a ▁system atic ▁means ▁of ▁compos ing ▁without ▁ton ality , ▁most ▁fam ously ▁the ▁method ▁of ▁compos ing ▁with ▁ 1 2 ▁t ones ▁or ▁the ▁twelve - t one ▁technique . ▁This ▁period ▁included ▁Berg ' s ▁L ulu ▁and ▁Ly ric ▁Su ite , ▁Sch o enberg ' s ▁P iano ▁Con cer to , ▁his ▁or atorio ▁Die ▁Jak obs le iter ▁and ▁numerous ▁smaller ▁pieces , ▁as ▁well ▁as ▁his ▁last ▁two ▁string ▁quart ets . ▁Sch o enberg ▁was ▁the ▁major ▁innov ator ▁of ▁the ▁system . ▁His ▁student , ▁Anton ▁We bern , ▁however , ▁is ▁an ec dot ally ▁claimed ▁to ▁have ▁begun ▁linking ▁dynamics ▁and ▁tone ▁color ▁to ▁the ▁primary ▁row , ▁making ▁rows ▁not ▁only ▁of ▁pitch es ▁but ▁of ▁other ▁aspects ▁of ▁music ▁as ▁well ▁. ▁However , ▁actual ▁analysis ▁of ▁We bern ' s ▁twelve - t one ▁works ▁has ▁so ▁far ▁failed