D’Addario pioneered the modern guitar string with the XL range. These were the strings that really put the D’Addario brand at the forefront of guitar strings where they’ve led ever since.
XLs were a result of necessity and some significant innovation in string making. The first was the utilising of a hexagonally-shaped steel core. A first in guitar strings, this core benefits from six points of contact which dig into the wrap wire allowing it to grip far better where it could otherwise slip on a round core. The additional benefit of the hex core is superior intonation and stability.
D’Addario’s second great innovation was the production and incorporation of machine-winding which alleviates all of the issues and inconsistencies of hand-winding - D’Addario is still the most consistent string making brand in the world.
And finally, the effects of war forced manufactures to look for alternatives to the skyrocketing price of nickel which was required for bullets, etc… . This led to D’Addario creating and utilising nickel-plated steel which has now become the industry standard.
Once combined with their own in-house wire-drawing and sourcing of raw materials D’Addario strings quickly became the leader in electric guitar strings!