The guitar had become the most popular instrument in the U.S. .
The Darco company came up with many innovations in the manufacture of guitar strings , including the first automated equipment to wind strings and the first roundwound bass guitar strings .
The guitar had become the most popular instrument in the U.S. , and the Darco company came up with many innovations in the manufacture of guitar strings , including the first automated equipment to wind strings and the first roundwound bass guitar strings .