D'Addario XT Phosphor Bronze Medium (.013–.056): the coated set that replaced EXP17
Reviewed by the Change Your Strings editorial team ·
D'Addario XT Phosphor Bronze Medium (XTAPB1356, .013 to .056) is D'Addario's current mid-tier coated acoustic set: a corrosion-resistant coating on all six strings, an NY Steel hex core, and Fusion Twist plain steels D'Addario rates 131% more tuning-stable than other acoustic strings. It's the current-catalog name for the coated Medium set behind Molly Tuttle's documented 2017 touring rig; D'Addario's own site now maps that legacy EXP17 model directly to this SKU.
What this set is
D'Addario XT Phosphor Bronze Medium is the company's current mid-tier coated acoustic set at its most common heavier gauge: .013 to .056, built on an NY Steel hex core with Fusion Twist plain steels, the same core technology that anchors D'Addario's NYXL electric line. A phosphor bronze wrap gives the warm, balanced tone the alloy is known for, and D'Addario's treated wrap wire is built into the wire itself rather than layered on top, which D'Addario says keeps the coated set closer to an uncoated string's natural feel.
It's also, per D'Addario's own EXP-to-XT transition page, the direct successor to a specific, documented product: EXP17. That page states the mapping outright, "EXP17 is now XTAPB1356." EXP17 is the exact model Premier Guitar's 2017 gear sidebar on Molly Tuttle named as her touring set. D'Addario hasn't published a newer statement reconfirming she plays the current XT-branded version, so this page treats that connection as historical context, the current-catalog name for the coated Medium gauge her documented rig used, not a live reconfirmed endorsement.
Anatomy
- Model
- D'Addario XT Phosphor Bronze Coated Medium
- SKU
- XTAPB1356
- Gauge
- .013 – .056 (Medium)
- Gauge set
- .013, .017, .026, .035, .045, .056
- String count
- 6 strings
- Core wire
- NY Steel hex core
- Wrap wire
- Phosphor bronze, XT treated wrap wire
- Coating
- XT treated wrap wire, all 6 strings (wound and plain steel)
- Construction
- Round wound, Fusion Twist plain steels
- High E (.013) tension
- 27.4 lbs (D'Addario spec)
- B (.017) tension
- 26.3 lbs (D'Addario spec)
- G (.026) tension
- 35.1 lbs (D'Addario spec)
- D (.035) tension
- 35.9 lbs (D'Addario spec)
- A (.045) tension
- 32.8 lbs (D'Addario spec)
- Low E (.056) tension
- 27.8 lbs (D'Addario spec)
- Made in
- United States (D'Addario, Farmingdale, NY)
XT Phosphor Bronze Coated Medium (.013–.056)
Why this one: D'Addario's current mid-tier coated Medium set: six-string treated-wrap protection and the NY Steel/Fusion Twist core tech from NYXL, at a lower price than the premium XS line.
Worth noting for anyone comparing tension numbers across gauges: the D and G strings carry more tension than either outer E string in this set, 35.9 and 35.1 lbs against 27.4 and 27.8 lbs. That's a normal feature of phosphor bronze construction, not a defect. The wound G string in a Medium set is thicker relative to its pitch than the plain high E, so it needs more tension to reach the same note.
From EXP to XT: what actually changed
D'Addario's own support article puts the three current coated tiers in order plainly: "XT is made with a treated wrap wire, which results in an extended lifespan over similar non-treated strings... XS is coated using a film coating which generally lasts even longer... Each string satisfies a particular need in the market. XT has replaced our successful EXP line as an excellent coated option, while XS utilizes our new, ultra-thin coating to bring a premium coated offering."
Two concrete upgrades over EXP, both sourced directly from D'Addario's transition page:
EXP to XT, what D'Addario actually changed
- String coverage
- EXP treated only the set's 3 to 4 wound strings. XT treats all 6, wound and plain steel, with a thinner coating that D'Addario says rings out closer to an uncoated string.
- Core and twist tech
- XT carries the NY Steel hex core and Fusion Twist plain-steel construction, the same technology D'Addario built into its NYXL electric line, which EXP did not have.
- Tuning stability
- D'Addario rates XT's Fusion Twist construction as staying in tune 131% better than other acoustic strings, a specific figure it publishes on the XTAPB1356 product page itself.
- Break resistance
- D'Addario markets XT's high-carbon NY Steel core as meaningfully more break-resistant than EXP's construction, framed as "extraordinary break resistance" on its own transition page.
Acoustic Guitar magazine's 2019 review of the XT line (Adam Perlmutter, testing .012-.053 Light gauge on a Gibson L-50 archtop and a Collings OM1A T flattop) is independent, non-D'Addario confirmation of the general pattern: strings that "seemed to require less tugging than normal to settle into pitch," held their brightness through weeks of daily test play, and felt "hardly noticeable" as coated despite the treatment. That review tested Light-gauge XT rather than this exact Medium 13-56 SKU, but both share the same XT construction and coating technology.
Compared to the alternatives
| D'Addario EJ17 | D'Addario XT (this set) | D'Addario XS | Elixir Nanoweb PB | |
|---|---|---|---|---|
| Gauge | .013–.056 (Medium) | .013–.056 (Medium) | .013–.056 (Medium) | .012–.053 (Light) |
| Coating | None, uncoated | Treated wrap wire, all 6 strings | Ultra-thin film coating | Nanoweb film |
| Core wire | Hex high-carbon steel | NY Steel hex core | NY Steel hex core | Hex steel |
| Tone character | Bright, articulate, full | Warm, balanced, natural | Warm, smooth, balanced | Warm, balanced |
| Lifespan | 3-8 weeks daily | Longer than uncoated (no exact figure published) | Longest in D'Addario's lineup (no exact figure published) | 8-24 weeks daily |
| Price tier | $ | $$ | $$ | $$ |
Note the gauge difference on the Elixir row: it's Light (.012-.053), not Medium. It's listed here as CYS's other reviewed coated acoustic reference point, not a gauge-for-gauge match. EJ17 and XS are the true apples-to-apples comparisons, same brand and gauge as this set.
Best for
Bluegrass and acoustic flatpickers who want six-string coated protection without paying XS's premium. Players who already like D'Addario's phosphor bronze tone and the NY Steel/Fusion Twist tech from NYXL and want it on an acoustic set. Anyone replacing an old EXP17 set who wants the direct current-catalog equivalent rather than hunting down discontinued stock. Touring or heavy-gigging players who restring often enough that EJ17's shorter uncoated life gets expensive.
Worst for
Players chasing the absolute longest coated lifespan; D'Addario's own support page says XS lasts even longer than XT, so step up to XS if maximum string life is the priority. Budget-first buyers who restring before every session anyway and would rather have EJ17's cheaper, brighter, uncoated tone. Smaller-bodied and vintage acoustics built for Light gauge, where Medium's extra tension isn't the right fit regardless of coating.
Verdict
XTAPB1356 is the sensible middle option in D'Addario's own three-tier Medium phosphor bronze lineup: more protection and tuning stability than uncoated EJ17, at a lower price than the premium XS line. It's also, quietly, the current identity of a real documented product, the coated set Premier Guitar tied to Molly Tuttle's touring rig back in 2017, before D'Addario folded EXP into XT sitewide.
If you want the coated feel without XS's price, or you're replacing an old EXP17 set and want D'Addario's own recommended current equivalent, this is the set. If maximum lifespan matters more than price, look at XS instead; if you don't mind restringing more often for a brighter, cheaper set, EJ17 is still the uncoated workhorse.
XT Phosphor Bronze Coated Medium (.013–.056)
Why this one: The direct current-catalog successor to EXP17, six-string treated-wrap protection at a lower price than XS.