ms ▁are ▁cone - sh aped . ▁ ▁Dia ph rag ms ▁are ▁also ▁found ▁in ▁head ph ones . ▁ ▁Qu ality ▁mid range ▁and ▁bass ▁drivers ▁are ▁usually ▁made ▁from ▁paper , ▁paper ▁compos ites ▁and ▁l amin ates , ▁pl astic ▁materials ▁such ▁as ▁poly pro py l ene , ▁or ▁min eral / fi ber ▁filled ▁poly pro py l ene . ▁ ▁Such ▁materials ▁have ▁very ▁high ▁strength / weight ▁r ati os ▁( paper ▁being ▁even ▁higher ▁than ▁met als ) ▁and ▁tend ▁to ▁be ▁relatively ▁imm une ▁from ▁flex ing ▁during ▁large ▁exc urs ions . ▁ ▁This ▁allows ▁the ▁driver ▁to ▁react ▁quickly ▁during ▁trans itions ▁in ▁music ▁( i . e . ▁fast ▁changing ▁trans ient ▁imp uls es ) ▁and ▁minim izes ▁ac oust ical ▁output ▁dist ort ion . ▁ ▁If ▁properly ▁designed ▁in ▁terms ▁of ▁mass , ▁st iff ness , ▁and ▁d amp ing , ▁paper ▁w oo fer / mid range ▁con es ▁can ▁out perform ▁many ▁ex otic ▁drivers ▁made ▁from ▁more ▁expensive ▁materials . ▁Other ▁materials ▁used ▁for ▁dia ph rag ms ▁include ▁poly pro py l ene ▁( PP ), ▁poly ether ether ket one ▁( PE E K ) ▁poly car bon ate ▁( PC ), ▁My lar ▁( P ET ), ▁sil k , ▁glass f ib re , ▁carbon ▁fib re , ▁tit an ium , ▁al umin ium , ▁al umin ium - m agn es ium ▁al loy , ▁nick el