The Martin MA550 SP Phosphor Bronze strings are built for acoustic players who want strong projection, rich tonal depth, and the solid feel of a true medium-gauge setup. Part of Martin’s Authentic Superior Performance series, these strings deliver warm balanced tone with the power and dynamic range many experienced acoustic players prefer.
Medium-gauge strings have long been favored by bluegrass players, heavy strummers, and musicians who want their guitar to respond with maximum fullness and volume. The MA550 set brings out deep lows, articulate mids, and smooth highs while preserving the natural acoustic character of the instrument.
For players who dig in confidently and want a guitar that pushes back a little under the hands, this set delivers that classic medium-string response.
The phosphor bronze construction provides balanced warmth and clarity without sounding overly bright or harsh. Chords feel rich and full while single-note lines maintain enough articulation to cut through naturally.
The medium .013-.056 gauge adds body and projection that many players find especially rewarding on dreadnoughts and larger-bodied acoustic guitars.
Medium strings require a little more hand strength than lighter gauges, but many players appreciate the payoff in volume, resonance, and tonal fullness. The added tension helps drive the top of the guitar harder, creating a more robust acoustic voice.
That makes the MA550 set especially popular for bluegrass, Americana, worship music, singer-songwriter styles, and aggressive rhythm playing.
Martin strings have earned the trust of acoustic musicians for generations because they consistently deliver stable tuning, reliable feel, and musical response. The SP series is designed to complement the natural resonance of acoustic instruments while maintaining durability and dependable everyday performance.
Good strings should help a guitar feel alive and responsive, and this set does exactly that for players who prefer the strength and depth of medium gauges.
At Roxy Music, we’ve helped acoustic players maintain and refine their instruments since 1939. We understand how much strings influence feel, projection, tuning stability, and overall playing confidence.
Whether you’re searching for a stronger acoustic setup, experimenting with different gauges, or dialing in your ideal tone, our staff can help you choose strings that fit your instrument and your playing style. Learn more about our family-owned music store on our About Us page.
The Martin MA550 SP Phosphor Bronze set delivers rich acoustic tone, dependable performance, and the powerful response medium-gauge players rely on for confident acoustic playing.
Questions? Call 219-362-2340 or contact us. Real musicians, no pressure.
