▁along ▁the ▁string ' s ▁length ▁or ▁per pend icular ▁to ▁it . ▁ ▁The ▁ple as antly ▁" al ive " ▁sound ▁of ▁a ▁large ▁string ▁section ▁results ▁from ▁the ▁amount ▁by ▁which ▁each ▁string ed ▁instrument ▁is ▁slightly ▁out ▁of ▁t une . ▁ ▁Fre tt ed ▁instrument ▁in ton ation ▁Several ▁factors ▁affect ▁fre tt ed ▁instrument ▁in ton ation , ▁including ▁depth ▁of ▁the ▁string ▁sl ots ▁in ▁the ▁nut , ▁bridge ▁s addle ▁position , ▁the ▁position ▁of ▁the ▁fre ts ▁themselves , ▁the ▁b ending ▁st iff ness ▁of ▁the ▁string , ▁and ▁the ▁technique ▁of ▁the ▁music ian . ▁ ▁On ▁fre tt ed ▁string ▁instruments , ▁pushing ▁a ▁string ▁against ▁a ▁f ret — as ide ▁from ▁raising ▁the ▁string ' s ▁pitch ▁because ▁its ▁effective ▁length ▁is ▁reduced — also ▁causes ▁a ▁slight ▁secondary ▁raise ▁in ▁pitch ▁because ▁pushing ▁the ▁string ▁increases ▁its ▁t ension . ▁If ▁the ▁instrument ▁doesn ' t ▁compens ate ▁for ▁this ▁with ▁a ▁slight ▁increase ▁in ▁the ▁distance ▁from ▁the ▁bridge ▁s addle ▁to ▁the ▁f ret , ▁the ▁note ▁sounds ▁sharp . ▁Play ing ▁technique ▁has ▁some ▁effect ▁on ▁in ton ation ▁but ▁some ▁amount ▁of ▁in ton ation ▁vari ability ▁may ▁be ▁un cont roll able . ▁ ▁Most ▁electric ▁fre tt ed ▁string ▁instruments ▁have ▁individually ▁adjust able ▁bridge ▁s add les , ▁adjust able ▁with ▁a ▁sc rew ▁driver ▁or ▁Allen ▁w rench . ▁Ac oust ic ▁fre tt ed ▁instruments ▁typically ▁have ▁either ▁a