▁floating ▁bridge , ▁held ▁in ▁place ▁by ▁string ▁t ension , ▁or ▁a ▁fixed ▁bridge , ▁such ▁as ▁a ▁pin ▁bridge ▁on ▁an ▁ac oust ic ▁guitar . ▁A ▁l uth ier ▁or ▁techn ician ▁adjust s ▁a ▁floating ▁bridge ▁simply ▁by ▁carefully ▁changing ▁its ▁position ▁until ▁the ▁in ton ation ▁is ▁correct . ▁Ad just ing ▁in ton ation ▁on ▁a ▁fixed ▁bridge ▁involves ▁carefully ▁sh aping ▁the ▁bridge ▁s addle ▁with ▁a ▁file ▁to ▁alter ▁the ▁string ' s ▁contact ▁point . ▁ ▁Another ▁cause ▁of ▁poor ▁in ton ation ▁on ▁a ▁fre tt ed ▁instrument ▁is ▁that ▁the ▁mak er ▁didn ' t ▁cut ▁the ▁string ▁sl ots ▁in ▁the ▁nut ▁deep ▁enough . ▁If ▁the ▁string ▁is ▁higher ▁than ▁f ret ▁height ▁at ▁the ▁nut , ▁the ▁string ▁def lection - ca used ▁pitch ▁increase ▁is ▁progress ively ▁greater ▁closer ▁to ▁the ▁nut . ▁ ▁Other ▁instruments ▁Like ▁un fre tt ed ▁string ▁instruments , ▁the ▁trom bone ▁re lies ▁on ▁the ▁music ian ▁precisely ▁position ing ▁something , ▁in ▁this ▁case ▁the ▁trom bone ' s ▁slide . ▁The ▁slide ' s ▁pitch ▁adjust ment ▁on ▁a ▁single ▁partial ▁is ▁approximately ▁the ▁interval ▁of ▁a ▁tr it one ▁on ▁a ▁slide ▁length ▁of ▁over ▁ 8 0 ▁cent im eters . ▁ ▁The ▁trom bon ist ▁may ▁use ▁his / her ▁ear ▁to ▁min utely ▁adjust ▁pitch ▁on ▁sust ained ▁notes . ▁ ▁By ▁coinc idence , ▁the ▁position ▁of ▁the ▁bell ▁on ▁most ▁trom b ones ▁provides