D'Addario EJ17 Phosphor Bronze Medium (.013–.056): the strummer's acoustic

D'Addario EJ17 is the Medium-gauge phosphor bronze acoustic set, .013 to .056, made in D'Addario's Farmingdale, NY facility continuously since the EJ acoustic line launched in 1974. The set is the working canon for heavy-strumming dreadnought players, bluegrass flatpickers, slide acoustic players, and anyone whose acoustic guitar needs more tension and projection than Light gauge delivers.

The phosphor bronze wrap (92% copper, 8% zinc) is the alloy that defines the modern warm, balanced acoustic tone. Hex high-carbon steel core. Standard roundwound construction.

A Medium-gauge acoustic set on a dreadnought-body guitar produces measurably more volume than a Light-gauge set. The mechanism is straightforward: heavier strings store and release more energy when picked or strummed, which drives the soundboard with more amplitude. Bluegrass flatpicking traditions are built around Medium gauge precisely because bluegrass venues are often unmiked rooms where projection over a banjo and a fiddle matters.

The trade is fretting effort. Medium-gauge strings under standard tuning sit at noticeably higher tension than Light gauge — roughly 30 to 35 lbs more total across the six strings. That additional tension means harder fretting pressure, more demanding bending, and more wrist load over a long set. Players who can handle the additional effort get the volume and projection benefit; players who can't end up with hand fatigue.

Bluegrass flatpicking on a dreadnought (the canon Medium gauge in this tradition). Heavy-strumming singer-songwriters whose right-hand attack drives the soundboard hard. Slide acoustic players in Open D, Open G, or DADGAD where the additional tension keeps the slide from rattling the strings against the frets. Studio session players who need acoustic projection that doesn't require heavy compression to balance against louder instruments. Players whose hands are strong enough to handle Medium tension without fatigue.

Vintage acoustics built for Light gauge (the additional tension can stress the bracing). Parlor and travel-body acoustics where the smaller soundbox doesn't benefit from the extra string energy. Fingerstyle players with smaller hands or borderline grip strength (stay on EJ16 Light). Acoustic-electric players who rely heavily on the under-saddle pickup — the additional tension can over-load some piezo systems and produce harsh attack peaks.

If your acoustic was designed for it, Medium gauge is louder and more projecting than Light, with a tone profile that suits aggressive strumming, bluegrass flatpicking, and slide playing. EJ17 is the workhorse Medium set from the largest acoustic string brand in North America, made in the same Farmingdale factory for over five decades. Pick this when your dreadnought needs more volume and your hands can handle the additional tension.