there are two different materials of the acoustic guitar strings. olympia 80/20 bronze strings deliver a strong, deep bass response with extremely bright and crisp overtones. these strings are made from 80/20 bronze. bronze 80/20 is an alloy of 80% copper and 20% zinc, they’re certain to bring that extremely brilliant sounding. these sets really come alive at the deep end with a solid. the other material acoustic guitar strings phosphor bronze, it is an alloy of cooper 90% and 10% zinc and last longer than conventional bronze alloy strings. also the small percentage of phosphorous in the alloy helps them to retain their sound longer. the strings vibrate more consistently and with greater amplitude to produce a sharper, more precise tone. note e b g d a e inch .012 .016 .024 .032 .042 .053