▁Audio ▁The ▁third - gener ation ▁i Pod ▁had ▁a ▁weak ▁bass ▁response , ▁as ▁shown ▁in ▁audio ▁tests . ▁The ▁combination ▁of ▁the ▁unders ized ▁DC - block ing ▁capac itors ▁and ▁the ▁typical ▁low ▁imped ance ▁of ▁most ▁consumer ▁head ph ones ▁form ▁a ▁high - pass ▁filter , ▁which ▁at ten u ates ▁the ▁low - fre quency ▁bass ▁output . ▁Similar ▁capac itors ▁were ▁used ▁in ▁the ▁fourth - gener ation ▁i P ods . ▁The ▁problem ▁is ▁reduced ▁when ▁using ▁high - imp ed ance ▁head ph ones ▁and ▁is ▁completely ▁mask ed ▁when ▁driving ▁high - imp ed ance ▁( line ▁level ) ▁loads , ▁such ▁as ▁an ▁external ▁head phone ▁ampl ifier . ▁The ▁first - gener ation ▁i Pod ▁Sh uffle ▁uses ▁a ▁dual - trans istor ▁output ▁stage , ▁rather ▁than ▁a ▁single ▁capac itor - cou ple d ▁output , ▁and ▁does ▁not ▁exhib it ▁reduced ▁bass ▁response ▁for ▁any ▁load . ▁ ▁For ▁all ▁i P ods ▁released ▁in ▁ 2 0 0 6 ▁and ▁earlier , ▁some ▁equal izer ▁( EQ ) ▁sound ▁settings ▁would ▁dist ort ▁the ▁bass ▁sound ▁far ▁too ▁easily , ▁even ▁on ▁und em and ing ▁songs . ▁This ▁would ▁happen ▁for ▁E Q ▁settings ▁like ▁R & B , ▁Rock , ▁Ac oust ic , ▁and ▁Bass ▁Bo oster , ▁because ▁the ▁equal izer ▁ampl ified ▁the ▁digital ▁audio ▁level ▁beyond ▁the ▁software ' s ▁limit , ▁causing ▁dist ort ion ▁( cli pping ) ▁on