I'm interested if people agree/disagree with these theories I've got about string types/construction and their tone and life. I think that string brightness comes from the string's flexibility- a hexagonal core, and round windings on it allow flexibility between the component parts of the string due to minimal contact between them- the harmonics of the string can "develop" better. tapering windings or an exposed core at the bridge allow greater flexibility and hence more brightness. on a Rotosound RS77 steel flatwound string there is a hexagonal core with a round winding over it, and a final flat surface winding. it sounds bright to begin with, but quickly becomes dull as sweat and dirt accumulate in the windings, trapped under the flat outer wrap more than a round winding would, and the flexibility of the string is reduced. there is greater contact between the trapped dirt and the flat winding than there'd be with a round winding also. boiling flat or roundwound strings flushes out the dirt, and brings back brightness. the Elixir goretex coating stops ingress of sweat and dirt to start with. maybe Maxima gold strings last longer because the gold plating prevents the adhesion of dirt, and also stops corrosion.